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1/*
2 * linux/fs/ext4/xattr.c
3 *
4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5 *
6 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
7 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
8 * Extended attributes for symlinks and special files added per
9 * suggestion of Luka Renko <luka.renko@hermes.si>.
10 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
11 * Red Hat Inc.
12 * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
13 * and Andreas Gruenbacher <agruen@suse.de>.
14 */
15
16/*
17 * Extended attributes are stored directly in inodes (on file systems with
18 * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
19 * field contains the block number if an inode uses an additional block. All
20 * attributes must fit in the inode and one additional block. Blocks that
21 * contain the identical set of attributes may be shared among several inodes.
22 * Identical blocks are detected by keeping a cache of blocks that have
23 * recently been accessed.
24 *
25 * The attributes in inodes and on blocks have a different header; the entries
26 * are stored in the same format:
27 *
28 * +------------------+
29 * | header |
30 * | entry 1 | |
31 * | entry 2 | | growing downwards
32 * | entry 3 | v
33 * | four null bytes |
34 * | . . . |
35 * | value 1 | ^
36 * | value 3 | | growing upwards
37 * | value 2 | |
38 * +------------------+
39 *
40 * The header is followed by multiple entry descriptors. In disk blocks, the
41 * entry descriptors are kept sorted. In inodes, they are unsorted. The
42 * attribute values are aligned to the end of the block in no specific order.
43 *
44 * Locking strategy
45 * ----------------
46 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
47 * EA blocks are only changed if they are exclusive to an inode, so
48 * holding xattr_sem also means that nothing but the EA block's reference
49 * count can change. Multiple writers to the same block are synchronized
50 * by the buffer lock.
51 */
52
53#include <linux/init.h>
54#include <linux/fs.h>
55#include <linux/slab.h>
56#include <linux/mbcache.h>
57#include <linux/quotaops.h>
58#include "ext4_jbd2.h"
59#include "ext4.h"
60#include "xattr.h"
61#include "acl.h"
62
63#ifdef EXT4_XATTR_DEBUG
64# define ea_idebug(inode, f...) do { \
65 printk(KERN_DEBUG "inode %s:%lu: ", \
66 inode->i_sb->s_id, inode->i_ino); \
67 printk(f); \
68 printk("\n"); \
69 } while (0)
70# define ea_bdebug(bh, f...) do { \
71 printk(KERN_DEBUG "block %pg:%lu: ", \
72 bh->b_bdev, (unsigned long) bh->b_blocknr); \
73 printk(f); \
74 printk("\n"); \
75 } while (0)
76#else
77# define ea_idebug(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
78# define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
79#endif
80
81static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
82static struct buffer_head *ext4_xattr_cache_find(struct inode *,
83 struct ext4_xattr_header *,
84 struct mb_cache_entry **);
85static void ext4_xattr_rehash(struct ext4_xattr_header *,
86 struct ext4_xattr_entry *);
87static int ext4_xattr_list(struct dentry *dentry, char *buffer,
88 size_t buffer_size);
89
90static const struct xattr_handler *ext4_xattr_handler_map[] = {
91 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
92#ifdef CONFIG_EXT4_FS_POSIX_ACL
93 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
94 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
95#endif
96 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
97#ifdef CONFIG_EXT4_FS_SECURITY
98 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
99#endif
100};
101
102const struct xattr_handler *ext4_xattr_handlers[] = {
103 &ext4_xattr_user_handler,
104 &ext4_xattr_trusted_handler,
105#ifdef CONFIG_EXT4_FS_POSIX_ACL
106 &posix_acl_access_xattr_handler,
107 &posix_acl_default_xattr_handler,
108#endif
109#ifdef CONFIG_EXT4_FS_SECURITY
110 &ext4_xattr_security_handler,
111#endif
112 NULL
113};
114
115#define EXT4_GET_MB_CACHE(inode) (((struct ext4_sb_info *) \
116 inode->i_sb->s_fs_info)->s_mb_cache)
117
118static __le32 ext4_xattr_block_csum(struct inode *inode,
119 sector_t block_nr,
120 struct ext4_xattr_header *hdr)
121{
122 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
123 __u32 csum;
124 __le32 save_csum;
125 __le64 dsk_block_nr = cpu_to_le64(block_nr);
126
127 save_csum = hdr->h_checksum;
128 hdr->h_checksum = 0;
129 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
130 sizeof(dsk_block_nr));
131 csum = ext4_chksum(sbi, csum, (__u8 *)hdr,
132 EXT4_BLOCK_SIZE(inode->i_sb));
133
134 hdr->h_checksum = save_csum;
135 return cpu_to_le32(csum);
136}
137
138static int ext4_xattr_block_csum_verify(struct inode *inode,
139 sector_t block_nr,
140 struct ext4_xattr_header *hdr)
141{
142 if (ext4_has_metadata_csum(inode->i_sb) &&
143 (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
144 return 0;
145 return 1;
146}
147
148static void ext4_xattr_block_csum_set(struct inode *inode,
149 sector_t block_nr,
150 struct ext4_xattr_header *hdr)
151{
152 if (!ext4_has_metadata_csum(inode->i_sb))
153 return;
154
155 hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
156}
157
158static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
159 struct inode *inode,
160 struct buffer_head *bh)
161{
162 ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
163 return ext4_handle_dirty_metadata(handle, inode, bh);
164}
165
166static inline const struct xattr_handler *
167ext4_xattr_handler(int name_index)
168{
169 const struct xattr_handler *handler = NULL;
170
171 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
172 handler = ext4_xattr_handler_map[name_index];
173 return handler;
174}
175
176/*
177 * Inode operation listxattr()
178 *
179 * d_inode(dentry)->i_mutex: don't care
180 */
181ssize_t
182ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
183{
184 return ext4_xattr_list(dentry, buffer, size);
185}
186
187static int
188ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end,
189 void *value_start)
190{
191 struct ext4_xattr_entry *e = entry;
192
193 while (!IS_LAST_ENTRY(e)) {
194 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
195 if ((void *)next >= end)
196 return -EFSCORRUPTED;
197 e = next;
198 }
199
200 while (!IS_LAST_ENTRY(entry)) {
201 if (entry->e_value_size != 0 &&
202 (value_start + le16_to_cpu(entry->e_value_offs) <
203 (void *)e + sizeof(__u32) ||
204 value_start + le16_to_cpu(entry->e_value_offs) +
205 le32_to_cpu(entry->e_value_size) > end))
206 return -EFSCORRUPTED;
207 entry = EXT4_XATTR_NEXT(entry);
208 }
209
210 return 0;
211}
212
213static inline int
214ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
215{
216 int error;
217
218 if (buffer_verified(bh))
219 return 0;
220
221 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
222 BHDR(bh)->h_blocks != cpu_to_le32(1))
223 return -EFSCORRUPTED;
224 if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
225 return -EFSBADCRC;
226 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size,
227 bh->b_data);
228 if (!error)
229 set_buffer_verified(bh);
230 return error;
231}
232
233static int
234__xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
235 void *end, const char *function, unsigned int line)
236{
237 struct ext4_xattr_entry *entry = IFIRST(header);
238 int error = -EFSCORRUPTED;
239
240 if (((void *) header >= end) ||
241 (header->h_magic != le32_to_cpu(EXT4_XATTR_MAGIC)))
242 goto errout;
243 error = ext4_xattr_check_names(entry, end, entry);
244errout:
245 if (error)
246 __ext4_error_inode(inode, function, line, 0,
247 "corrupted in-inode xattr");
248 return error;
249}
250
251#define xattr_check_inode(inode, header, end) \
252 __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
253
254static inline int
255ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
256{
257 size_t value_size = le32_to_cpu(entry->e_value_size);
258
259 if (entry->e_value_block != 0 || value_size > size ||
260 le16_to_cpu(entry->e_value_offs) + value_size > size)
261 return -EFSCORRUPTED;
262 return 0;
263}
264
265static int
266ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
267 const char *name, size_t size, int sorted)
268{
269 struct ext4_xattr_entry *entry;
270 size_t name_len;
271 int cmp = 1;
272
273 if (name == NULL)
274 return -EINVAL;
275 name_len = strlen(name);
276 entry = *pentry;
277 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
278 cmp = name_index - entry->e_name_index;
279 if (!cmp)
280 cmp = name_len - entry->e_name_len;
281 if (!cmp)
282 cmp = memcmp(name, entry->e_name, name_len);
283 if (cmp <= 0 && (sorted || cmp == 0))
284 break;
285 }
286 *pentry = entry;
287 if (!cmp && ext4_xattr_check_entry(entry, size))
288 return -EFSCORRUPTED;
289 return cmp ? -ENODATA : 0;
290}
291
292static int
293ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
294 void *buffer, size_t buffer_size)
295{
296 struct buffer_head *bh = NULL;
297 struct ext4_xattr_entry *entry;
298 size_t size;
299 int error;
300 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
301
302 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
303 name_index, name, buffer, (long)buffer_size);
304
305 error = -ENODATA;
306 if (!EXT4_I(inode)->i_file_acl)
307 goto cleanup;
308 ea_idebug(inode, "reading block %llu",
309 (unsigned long long)EXT4_I(inode)->i_file_acl);
310 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
311 if (!bh)
312 goto cleanup;
313 ea_bdebug(bh, "b_count=%d, refcount=%d",
314 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
315 if (ext4_xattr_check_block(inode, bh)) {
316bad_block:
317 EXT4_ERROR_INODE(inode, "bad block %llu",
318 EXT4_I(inode)->i_file_acl);
319 error = -EFSCORRUPTED;
320 goto cleanup;
321 }
322 ext4_xattr_cache_insert(ext4_mb_cache, bh);
323 entry = BFIRST(bh);
324 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
325 if (error == -EFSCORRUPTED)
326 goto bad_block;
327 if (error)
328 goto cleanup;
329 size = le32_to_cpu(entry->e_value_size);
330 if (buffer) {
331 error = -ERANGE;
332 if (size > buffer_size)
333 goto cleanup;
334 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
335 size);
336 }
337 error = size;
338
339cleanup:
340 brelse(bh);
341 return error;
342}
343
344int
345ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
346 void *buffer, size_t buffer_size)
347{
348 struct ext4_xattr_ibody_header *header;
349 struct ext4_xattr_entry *entry;
350 struct ext4_inode *raw_inode;
351 struct ext4_iloc iloc;
352 size_t size;
353 void *end;
354 int error;
355
356 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
357 return -ENODATA;
358 error = ext4_get_inode_loc(inode, &iloc);
359 if (error)
360 return error;
361 raw_inode = ext4_raw_inode(&iloc);
362 header = IHDR(inode, raw_inode);
363 entry = IFIRST(header);
364 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
365 error = xattr_check_inode(inode, header, end);
366 if (error)
367 goto cleanup;
368 error = ext4_xattr_find_entry(&entry, name_index, name,
369 end - (void *)entry, 0);
370 if (error)
371 goto cleanup;
372 size = le32_to_cpu(entry->e_value_size);
373 if (buffer) {
374 error = -ERANGE;
375 if (size > buffer_size)
376 goto cleanup;
377 memcpy(buffer, (void *)IFIRST(header) +
378 le16_to_cpu(entry->e_value_offs), size);
379 }
380 error = size;
381
382cleanup:
383 brelse(iloc.bh);
384 return error;
385}
386
387/*
388 * ext4_xattr_get()
389 *
390 * Copy an extended attribute into the buffer
391 * provided, or compute the buffer size required.
392 * Buffer is NULL to compute the size of the buffer required.
393 *
394 * Returns a negative error number on failure, or the number of bytes
395 * used / required on success.
396 */
397int
398ext4_xattr_get(struct inode *inode, int name_index, const char *name,
399 void *buffer, size_t buffer_size)
400{
401 int error;
402
403 if (strlen(name) > 255)
404 return -ERANGE;
405
406 down_read(&EXT4_I(inode)->xattr_sem);
407 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
408 buffer_size);
409 if (error == -ENODATA)
410 error = ext4_xattr_block_get(inode, name_index, name, buffer,
411 buffer_size);
412 up_read(&EXT4_I(inode)->xattr_sem);
413 return error;
414}
415
416static int
417ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
418 char *buffer, size_t buffer_size)
419{
420 size_t rest = buffer_size;
421
422 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
423 const struct xattr_handler *handler =
424 ext4_xattr_handler(entry->e_name_index);
425
426 if (handler && (!handler->list || handler->list(dentry))) {
427 const char *prefix = handler->prefix ?: handler->name;
428 size_t prefix_len = strlen(prefix);
429 size_t size = prefix_len + entry->e_name_len + 1;
430
431 if (buffer) {
432 if (size > rest)
433 return -ERANGE;
434 memcpy(buffer, prefix, prefix_len);
435 buffer += prefix_len;
436 memcpy(buffer, entry->e_name, entry->e_name_len);
437 buffer += entry->e_name_len;
438 *buffer++ = 0;
439 }
440 rest -= size;
441 }
442 }
443 return buffer_size - rest; /* total size */
444}
445
446static int
447ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
448{
449 struct inode *inode = d_inode(dentry);
450 struct buffer_head *bh = NULL;
451 int error;
452 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
453
454 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
455 buffer, (long)buffer_size);
456
457 error = 0;
458 if (!EXT4_I(inode)->i_file_acl)
459 goto cleanup;
460 ea_idebug(inode, "reading block %llu",
461 (unsigned long long)EXT4_I(inode)->i_file_acl);
462 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
463 error = -EIO;
464 if (!bh)
465 goto cleanup;
466 ea_bdebug(bh, "b_count=%d, refcount=%d",
467 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
468 if (ext4_xattr_check_block(inode, bh)) {
469 EXT4_ERROR_INODE(inode, "bad block %llu",
470 EXT4_I(inode)->i_file_acl);
471 error = -EFSCORRUPTED;
472 goto cleanup;
473 }
474 ext4_xattr_cache_insert(ext4_mb_cache, bh);
475 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
476
477cleanup:
478 brelse(bh);
479
480 return error;
481}
482
483static int
484ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
485{
486 struct inode *inode = d_inode(dentry);
487 struct ext4_xattr_ibody_header *header;
488 struct ext4_inode *raw_inode;
489 struct ext4_iloc iloc;
490 void *end;
491 int error;
492
493 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
494 return 0;
495 error = ext4_get_inode_loc(inode, &iloc);
496 if (error)
497 return error;
498 raw_inode = ext4_raw_inode(&iloc);
499 header = IHDR(inode, raw_inode);
500 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
501 error = xattr_check_inode(inode, header, end);
502 if (error)
503 goto cleanup;
504 error = ext4_xattr_list_entries(dentry, IFIRST(header),
505 buffer, buffer_size);
506
507cleanup:
508 brelse(iloc.bh);
509 return error;
510}
511
512/*
513 * ext4_xattr_list()
514 *
515 * Copy a list of attribute names into the buffer
516 * provided, or compute the buffer size required.
517 * Buffer is NULL to compute the size of the buffer required.
518 *
519 * Returns a negative error number on failure, or the number of bytes
520 * used / required on success.
521 */
522static int
523ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
524{
525 int ret, ret2;
526
527 down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
528 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
529 if (ret < 0)
530 goto errout;
531 if (buffer) {
532 buffer += ret;
533 buffer_size -= ret;
534 }
535 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
536 if (ret < 0)
537 goto errout;
538 ret += ret2;
539errout:
540 up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
541 return ret;
542}
543
544/*
545 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
546 * not set, set it.
547 */
548static void ext4_xattr_update_super_block(handle_t *handle,
549 struct super_block *sb)
550{
551 if (ext4_has_feature_xattr(sb))
552 return;
553
554 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
555 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
556 ext4_set_feature_xattr(sb);
557 ext4_handle_dirty_super(handle, sb);
558 }
559}
560
561/*
562 * Release the xattr block BH: If the reference count is > 1, decrement it;
563 * otherwise free the block.
564 */
565static void
566ext4_xattr_release_block(handle_t *handle, struct inode *inode,
567 struct buffer_head *bh)
568{
569 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
570 u32 hash, ref;
571 int error = 0;
572
573 BUFFER_TRACE(bh, "get_write_access");
574 error = ext4_journal_get_write_access(handle, bh);
575 if (error)
576 goto out;
577
578 lock_buffer(bh);
579 hash = le32_to_cpu(BHDR(bh)->h_hash);
580 ref = le32_to_cpu(BHDR(bh)->h_refcount);
581 if (ref == 1) {
582 ea_bdebug(bh, "refcount now=0; freeing");
583 /*
584 * This must happen under buffer lock for
585 * ext4_xattr_block_set() to reliably detect freed block
586 */
587 mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr);
588 get_bh(bh);
589 unlock_buffer(bh);
590 ext4_free_blocks(handle, inode, bh, 0, 1,
591 EXT4_FREE_BLOCKS_METADATA |
592 EXT4_FREE_BLOCKS_FORGET);
593 } else {
594 ref--;
595 BHDR(bh)->h_refcount = cpu_to_le32(ref);
596 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
597 struct mb_cache_entry *ce;
598
599 ce = mb_cache_entry_get(ext4_mb_cache, hash,
600 bh->b_blocknr);
601 if (ce) {
602 ce->e_reusable = 1;
603 mb_cache_entry_put(ext4_mb_cache, ce);
604 }
605 }
606
607 /*
608 * Beware of this ugliness: Releasing of xattr block references
609 * from different inodes can race and so we have to protect
610 * from a race where someone else frees the block (and releases
611 * its journal_head) before we are done dirtying the buffer. In
612 * nojournal mode this race is harmless and we actually cannot
613 * call ext4_handle_dirty_xattr_block() with locked buffer as
614 * that function can call sync_dirty_buffer() so for that case
615 * we handle the dirtying after unlocking the buffer.
616 */
617 if (ext4_handle_valid(handle))
618 error = ext4_handle_dirty_xattr_block(handle, inode,
619 bh);
620 unlock_buffer(bh);
621 if (!ext4_handle_valid(handle))
622 error = ext4_handle_dirty_xattr_block(handle, inode,
623 bh);
624 if (IS_SYNC(inode))
625 ext4_handle_sync(handle);
626 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
627 ea_bdebug(bh, "refcount now=%d; releasing",
628 le32_to_cpu(BHDR(bh)->h_refcount));
629 }
630out:
631 ext4_std_error(inode->i_sb, error);
632 return;
633}
634
635/*
636 * Find the available free space for EAs. This also returns the total number of
637 * bytes used by EA entries.
638 */
639static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
640 size_t *min_offs, void *base, int *total)
641{
642 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
643 if (!last->e_value_block && last->e_value_size) {
644 size_t offs = le16_to_cpu(last->e_value_offs);
645 if (offs < *min_offs)
646 *min_offs = offs;
647 }
648 if (total)
649 *total += EXT4_XATTR_LEN(last->e_name_len);
650 }
651 return (*min_offs - ((void *)last - base) - sizeof(__u32));
652}
653
654static int
655ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
656{
657 struct ext4_xattr_entry *last;
658 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
659
660 /* Compute min_offs and last. */
661 last = s->first;
662 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
663 if (!last->e_value_block && last->e_value_size) {
664 size_t offs = le16_to_cpu(last->e_value_offs);
665 if (offs < min_offs)
666 min_offs = offs;
667 }
668 }
669 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
670 if (!s->not_found) {
671 if (!s->here->e_value_block && s->here->e_value_size) {
672 size_t size = le32_to_cpu(s->here->e_value_size);
673 free += EXT4_XATTR_SIZE(size);
674 }
675 free += EXT4_XATTR_LEN(name_len);
676 }
677 if (i->value) {
678 if (free < EXT4_XATTR_LEN(name_len) +
679 EXT4_XATTR_SIZE(i->value_len))
680 return -ENOSPC;
681 }
682
683 if (i->value && s->not_found) {
684 /* Insert the new name. */
685 size_t size = EXT4_XATTR_LEN(name_len);
686 size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
687 memmove((void *)s->here + size, s->here, rest);
688 memset(s->here, 0, size);
689 s->here->e_name_index = i->name_index;
690 s->here->e_name_len = name_len;
691 memcpy(s->here->e_name, i->name, name_len);
692 } else {
693 if (!s->here->e_value_block && s->here->e_value_size) {
694 void *first_val = s->base + min_offs;
695 size_t offs = le16_to_cpu(s->here->e_value_offs);
696 void *val = s->base + offs;
697 size_t size = EXT4_XATTR_SIZE(
698 le32_to_cpu(s->here->e_value_size));
699
700 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
701 /* The old and the new value have the same
702 size. Just replace. */
703 s->here->e_value_size =
704 cpu_to_le32(i->value_len);
705 if (i->value == EXT4_ZERO_XATTR_VALUE) {
706 memset(val, 0, size);
707 } else {
708 /* Clear pad bytes first. */
709 memset(val + size - EXT4_XATTR_PAD, 0,
710 EXT4_XATTR_PAD);
711 memcpy(val, i->value, i->value_len);
712 }
713 return 0;
714 }
715
716 /* Remove the old value. */
717 memmove(first_val + size, first_val, val - first_val);
718 memset(first_val, 0, size);
719 s->here->e_value_size = 0;
720 s->here->e_value_offs = 0;
721 min_offs += size;
722
723 /* Adjust all value offsets. */
724 last = s->first;
725 while (!IS_LAST_ENTRY(last)) {
726 size_t o = le16_to_cpu(last->e_value_offs);
727 if (!last->e_value_block &&
728 last->e_value_size && o < offs)
729 last->e_value_offs =
730 cpu_to_le16(o + size);
731 last = EXT4_XATTR_NEXT(last);
732 }
733 }
734 if (!i->value) {
735 /* Remove the old name. */
736 size_t size = EXT4_XATTR_LEN(name_len);
737 last = ENTRY((void *)last - size);
738 memmove(s->here, (void *)s->here + size,
739 (void *)last - (void *)s->here + sizeof(__u32));
740 memset(last, 0, size);
741 }
742 }
743
744 if (i->value) {
745 /* Insert the new value. */
746 s->here->e_value_size = cpu_to_le32(i->value_len);
747 if (i->value_len) {
748 size_t size = EXT4_XATTR_SIZE(i->value_len);
749 void *val = s->base + min_offs - size;
750 s->here->e_value_offs = cpu_to_le16(min_offs - size);
751 if (i->value == EXT4_ZERO_XATTR_VALUE) {
752 memset(val, 0, size);
753 } else {
754 /* Clear the pad bytes first. */
755 memset(val + size - EXT4_XATTR_PAD, 0,
756 EXT4_XATTR_PAD);
757 memcpy(val, i->value, i->value_len);
758 }
759 }
760 }
761 return 0;
762}
763
764struct ext4_xattr_block_find {
765 struct ext4_xattr_search s;
766 struct buffer_head *bh;
767};
768
769static int
770ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
771 struct ext4_xattr_block_find *bs)
772{
773 struct super_block *sb = inode->i_sb;
774 int error;
775
776 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
777 i->name_index, i->name, i->value, (long)i->value_len);
778
779 if (EXT4_I(inode)->i_file_acl) {
780 /* The inode already has an extended attribute block. */
781 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
782 error = -EIO;
783 if (!bs->bh)
784 goto cleanup;
785 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
786 atomic_read(&(bs->bh->b_count)),
787 le32_to_cpu(BHDR(bs->bh)->h_refcount));
788 if (ext4_xattr_check_block(inode, bs->bh)) {
789 EXT4_ERROR_INODE(inode, "bad block %llu",
790 EXT4_I(inode)->i_file_acl);
791 error = -EFSCORRUPTED;
792 goto cleanup;
793 }
794 /* Find the named attribute. */
795 bs->s.base = BHDR(bs->bh);
796 bs->s.first = BFIRST(bs->bh);
797 bs->s.end = bs->bh->b_data + bs->bh->b_size;
798 bs->s.here = bs->s.first;
799 error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
800 i->name, bs->bh->b_size, 1);
801 if (error && error != -ENODATA)
802 goto cleanup;
803 bs->s.not_found = error;
804 }
805 error = 0;
806
807cleanup:
808 return error;
809}
810
811static int
812ext4_xattr_block_set(handle_t *handle, struct inode *inode,
813 struct ext4_xattr_info *i,
814 struct ext4_xattr_block_find *bs)
815{
816 struct super_block *sb = inode->i_sb;
817 struct buffer_head *new_bh = NULL;
818 struct ext4_xattr_search *s = &bs->s;
819 struct mb_cache_entry *ce = NULL;
820 int error = 0;
821 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
822
823#define header(x) ((struct ext4_xattr_header *)(x))
824
825 if (i->value && i->value_len > sb->s_blocksize)
826 return -ENOSPC;
827 if (s->base) {
828 BUFFER_TRACE(bs->bh, "get_write_access");
829 error = ext4_journal_get_write_access(handle, bs->bh);
830 if (error)
831 goto cleanup;
832 lock_buffer(bs->bh);
833
834 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
835 __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
836
837 /*
838 * This must happen under buffer lock for
839 * ext4_xattr_block_set() to reliably detect modified
840 * block
841 */
842 mb_cache_entry_delete_block(ext4_mb_cache, hash,
843 bs->bh->b_blocknr);
844 ea_bdebug(bs->bh, "modifying in-place");
845 error = ext4_xattr_set_entry(i, s);
846 if (!error) {
847 if (!IS_LAST_ENTRY(s->first))
848 ext4_xattr_rehash(header(s->base),
849 s->here);
850 ext4_xattr_cache_insert(ext4_mb_cache,
851 bs->bh);
852 }
853 unlock_buffer(bs->bh);
854 if (error == -EFSCORRUPTED)
855 goto bad_block;
856 if (!error)
857 error = ext4_handle_dirty_xattr_block(handle,
858 inode,
859 bs->bh);
860 if (error)
861 goto cleanup;
862 goto inserted;
863 } else {
864 int offset = (char *)s->here - bs->bh->b_data;
865
866 unlock_buffer(bs->bh);
867 ea_bdebug(bs->bh, "cloning");
868 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
869 error = -ENOMEM;
870 if (s->base == NULL)
871 goto cleanup;
872 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
873 s->first = ENTRY(header(s->base)+1);
874 header(s->base)->h_refcount = cpu_to_le32(1);
875 s->here = ENTRY(s->base + offset);
876 s->end = s->base + bs->bh->b_size;
877 }
878 } else {
879 /* Allocate a buffer where we construct the new block. */
880 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
881 /* assert(header == s->base) */
882 error = -ENOMEM;
883 if (s->base == NULL)
884 goto cleanup;
885 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
886 header(s->base)->h_blocks = cpu_to_le32(1);
887 header(s->base)->h_refcount = cpu_to_le32(1);
888 s->first = ENTRY(header(s->base)+1);
889 s->here = ENTRY(header(s->base)+1);
890 s->end = s->base + sb->s_blocksize;
891 }
892
893 error = ext4_xattr_set_entry(i, s);
894 if (error == -EFSCORRUPTED)
895 goto bad_block;
896 if (error)
897 goto cleanup;
898 if (!IS_LAST_ENTRY(s->first))
899 ext4_xattr_rehash(header(s->base), s->here);
900
901inserted:
902 if (!IS_LAST_ENTRY(s->first)) {
903 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
904 if (new_bh) {
905 /* We found an identical block in the cache. */
906 if (new_bh == bs->bh)
907 ea_bdebug(new_bh, "keeping");
908 else {
909 u32 ref;
910
911 /* The old block is released after updating
912 the inode. */
913 error = dquot_alloc_block(inode,
914 EXT4_C2B(EXT4_SB(sb), 1));
915 if (error)
916 goto cleanup;
917 BUFFER_TRACE(new_bh, "get_write_access");
918 error = ext4_journal_get_write_access(handle,
919 new_bh);
920 if (error)
921 goto cleanup_dquot;
922 lock_buffer(new_bh);
923 /*
924 * We have to be careful about races with
925 * freeing, rehashing or adding references to
926 * xattr block. Once we hold buffer lock xattr
927 * block's state is stable so we can check
928 * whether the block got freed / rehashed or
929 * not. Since we unhash mbcache entry under
930 * buffer lock when freeing / rehashing xattr
931 * block, checking whether entry is still
932 * hashed is reliable. Same rules hold for
933 * e_reusable handling.
934 */
935 if (hlist_bl_unhashed(&ce->e_hash_list) ||
936 !ce->e_reusable) {
937 /*
938 * Undo everything and check mbcache
939 * again.
940 */
941 unlock_buffer(new_bh);
942 dquot_free_block(inode,
943 EXT4_C2B(EXT4_SB(sb),
944 1));
945 brelse(new_bh);
946 mb_cache_entry_put(ext4_mb_cache, ce);
947 ce = NULL;
948 new_bh = NULL;
949 goto inserted;
950 }
951 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
952 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
953 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
954 ce->e_reusable = 0;
955 ea_bdebug(new_bh, "reusing; refcount now=%d",
956 ref);
957 unlock_buffer(new_bh);
958 error = ext4_handle_dirty_xattr_block(handle,
959 inode,
960 new_bh);
961 if (error)
962 goto cleanup_dquot;
963 }
964 mb_cache_entry_touch(ext4_mb_cache, ce);
965 mb_cache_entry_put(ext4_mb_cache, ce);
966 ce = NULL;
967 } else if (bs->bh && s->base == bs->bh->b_data) {
968 /* We were modifying this block in-place. */
969 ea_bdebug(bs->bh, "keeping this block");
970 new_bh = bs->bh;
971 get_bh(new_bh);
972 } else {
973 /* We need to allocate a new block */
974 ext4_fsblk_t goal, block;
975
976 goal = ext4_group_first_block_no(sb,
977 EXT4_I(inode)->i_block_group);
978
979 /* non-extent files can't have physical blocks past 2^32 */
980 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
981 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
982
983 block = ext4_new_meta_blocks(handle, inode, goal, 0,
984 NULL, &error);
985 if (error)
986 goto cleanup;
987
988 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
989 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
990
991 ea_idebug(inode, "creating block %llu",
992 (unsigned long long)block);
993
994 new_bh = sb_getblk(sb, block);
995 if (unlikely(!new_bh)) {
996 error = -ENOMEM;
997getblk_failed:
998 ext4_free_blocks(handle, inode, NULL, block, 1,
999 EXT4_FREE_BLOCKS_METADATA);
1000 goto cleanup;
1001 }
1002 lock_buffer(new_bh);
1003 error = ext4_journal_get_create_access(handle, new_bh);
1004 if (error) {
1005 unlock_buffer(new_bh);
1006 error = -EIO;
1007 goto getblk_failed;
1008 }
1009 memcpy(new_bh->b_data, s->base, new_bh->b_size);
1010 set_buffer_uptodate(new_bh);
1011 unlock_buffer(new_bh);
1012 ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
1013 error = ext4_handle_dirty_xattr_block(handle,
1014 inode, new_bh);
1015 if (error)
1016 goto cleanup;
1017 }
1018 }
1019
1020 /* Update the inode. */
1021 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
1022
1023 /* Drop the previous xattr block. */
1024 if (bs->bh && bs->bh != new_bh)
1025 ext4_xattr_release_block(handle, inode, bs->bh);
1026 error = 0;
1027
1028cleanup:
1029 if (ce)
1030 mb_cache_entry_put(ext4_mb_cache, ce);
1031 brelse(new_bh);
1032 if (!(bs->bh && s->base == bs->bh->b_data))
1033 kfree(s->base);
1034
1035 return error;
1036
1037cleanup_dquot:
1038 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
1039 goto cleanup;
1040
1041bad_block:
1042 EXT4_ERROR_INODE(inode, "bad block %llu",
1043 EXT4_I(inode)->i_file_acl);
1044 goto cleanup;
1045
1046#undef header
1047}
1048
1049int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
1050 struct ext4_xattr_ibody_find *is)
1051{
1052 struct ext4_xattr_ibody_header *header;
1053 struct ext4_inode *raw_inode;
1054 int error;
1055
1056 if (EXT4_I(inode)->i_extra_isize == 0)
1057 return 0;
1058 raw_inode = ext4_raw_inode(&is->iloc);
1059 header = IHDR(inode, raw_inode);
1060 is->s.base = is->s.first = IFIRST(header);
1061 is->s.here = is->s.first;
1062 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1063 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
1064 error = xattr_check_inode(inode, header, is->s.end);
1065 if (error)
1066 return error;
1067 /* Find the named attribute. */
1068 error = ext4_xattr_find_entry(&is->s.here, i->name_index,
1069 i->name, is->s.end -
1070 (void *)is->s.base, 0);
1071 if (error && error != -ENODATA)
1072 return error;
1073 is->s.not_found = error;
1074 }
1075 return 0;
1076}
1077
1078int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
1079 struct ext4_xattr_info *i,
1080 struct ext4_xattr_ibody_find *is)
1081{
1082 struct ext4_xattr_ibody_header *header;
1083 struct ext4_xattr_search *s = &is->s;
1084 int error;
1085
1086 if (EXT4_I(inode)->i_extra_isize == 0)
1087 return -ENOSPC;
1088 error = ext4_xattr_set_entry(i, s);
1089 if (error) {
1090 if (error == -ENOSPC &&
1091 ext4_has_inline_data(inode)) {
1092 error = ext4_try_to_evict_inline_data(handle, inode,
1093 EXT4_XATTR_LEN(strlen(i->name) +
1094 EXT4_XATTR_SIZE(i->value_len)));
1095 if (error)
1096 return error;
1097 error = ext4_xattr_ibody_find(inode, i, is);
1098 if (error)
1099 return error;
1100 error = ext4_xattr_set_entry(i, s);
1101 }
1102 if (error)
1103 return error;
1104 }
1105 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1106 if (!IS_LAST_ENTRY(s->first)) {
1107 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1108 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1109 } else {
1110 header->h_magic = cpu_to_le32(0);
1111 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1112 }
1113 return 0;
1114}
1115
1116static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
1117 struct ext4_xattr_info *i,
1118 struct ext4_xattr_ibody_find *is)
1119{
1120 struct ext4_xattr_ibody_header *header;
1121 struct ext4_xattr_search *s = &is->s;
1122 int error;
1123
1124 if (EXT4_I(inode)->i_extra_isize == 0)
1125 return -ENOSPC;
1126 error = ext4_xattr_set_entry(i, s);
1127 if (error)
1128 return error;
1129 header = IHDR(inode, ext4_raw_inode(&is->iloc));
1130 if (!IS_LAST_ENTRY(s->first)) {
1131 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1132 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
1133 } else {
1134 header->h_magic = cpu_to_le32(0);
1135 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
1136 }
1137 return 0;
1138}
1139
1140static int ext4_xattr_value_same(struct ext4_xattr_search *s,
1141 struct ext4_xattr_info *i)
1142{
1143 void *value;
1144
1145 if (le32_to_cpu(s->here->e_value_size) != i->value_len)
1146 return 0;
1147 value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
1148 return !memcmp(value, i->value, i->value_len);
1149}
1150
1151/*
1152 * ext4_xattr_set_handle()
1153 *
1154 * Create, replace or remove an extended attribute for this inode. Value
1155 * is NULL to remove an existing extended attribute, and non-NULL to
1156 * either replace an existing extended attribute, or create a new extended
1157 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
1158 * specify that an extended attribute must exist and must not exist
1159 * previous to the call, respectively.
1160 *
1161 * Returns 0, or a negative error number on failure.
1162 */
1163int
1164ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
1165 const char *name, const void *value, size_t value_len,
1166 int flags)
1167{
1168 struct ext4_xattr_info i = {
1169 .name_index = name_index,
1170 .name = name,
1171 .value = value,
1172 .value_len = value_len,
1173
1174 };
1175 struct ext4_xattr_ibody_find is = {
1176 .s = { .not_found = -ENODATA, },
1177 };
1178 struct ext4_xattr_block_find bs = {
1179 .s = { .not_found = -ENODATA, },
1180 };
1181 unsigned long no_expand;
1182 int error;
1183
1184 if (!name)
1185 return -EINVAL;
1186 if (strlen(name) > 255)
1187 return -ERANGE;
1188 down_write(&EXT4_I(inode)->xattr_sem);
1189 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
1190 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
1191
1192 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
1193 if (error)
1194 goto cleanup;
1195
1196 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
1197 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
1198 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
1199 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
1200 }
1201
1202 error = ext4_xattr_ibody_find(inode, &i, &is);
1203 if (error)
1204 goto cleanup;
1205 if (is.s.not_found)
1206 error = ext4_xattr_block_find(inode, &i, &bs);
1207 if (error)
1208 goto cleanup;
1209 if (is.s.not_found && bs.s.not_found) {
1210 error = -ENODATA;
1211 if (flags & XATTR_REPLACE)
1212 goto cleanup;
1213 error = 0;
1214 if (!value)
1215 goto cleanup;
1216 } else {
1217 error = -EEXIST;
1218 if (flags & XATTR_CREATE)
1219 goto cleanup;
1220 }
1221 if (!value) {
1222 if (!is.s.not_found)
1223 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1224 else if (!bs.s.not_found)
1225 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1226 } else {
1227 error = 0;
1228 /* Xattr value did not change? Save us some work and bail out */
1229 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
1230 goto cleanup;
1231 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
1232 goto cleanup;
1233
1234 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
1235 if (!error && !bs.s.not_found) {
1236 i.value = NULL;
1237 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1238 } else if (error == -ENOSPC) {
1239 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
1240 error = ext4_xattr_block_find(inode, &i, &bs);
1241 if (error)
1242 goto cleanup;
1243 }
1244 error = ext4_xattr_block_set(handle, inode, &i, &bs);
1245 if (error)
1246 goto cleanup;
1247 if (!is.s.not_found) {
1248 i.value = NULL;
1249 error = ext4_xattr_ibody_set(handle, inode, &i,
1250 &is);
1251 }
1252 }
1253 }
1254 if (!error) {
1255 ext4_xattr_update_super_block(handle, inode->i_sb);
1256 inode->i_ctime = ext4_current_time(inode);
1257 if (!value)
1258 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1259 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
1260 /*
1261 * The bh is consumed by ext4_mark_iloc_dirty, even with
1262 * error != 0.
1263 */
1264 is.iloc.bh = NULL;
1265 if (IS_SYNC(inode))
1266 ext4_handle_sync(handle);
1267 }
1268
1269cleanup:
1270 brelse(is.iloc.bh);
1271 brelse(bs.bh);
1272 if (no_expand == 0)
1273 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
1274 up_write(&EXT4_I(inode)->xattr_sem);
1275 return error;
1276}
1277
1278/*
1279 * ext4_xattr_set()
1280 *
1281 * Like ext4_xattr_set_handle, but start from an inode. This extended
1282 * attribute modification is a filesystem transaction by itself.
1283 *
1284 * Returns 0, or a negative error number on failure.
1285 */
1286int
1287ext4_xattr_set(struct inode *inode, int name_index, const char *name,
1288 const void *value, size_t value_len, int flags)
1289{
1290 handle_t *handle;
1291 int error, retries = 0;
1292 int credits = ext4_jbd2_credits_xattr(inode);
1293
1294retry:
1295 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
1296 if (IS_ERR(handle)) {
1297 error = PTR_ERR(handle);
1298 } else {
1299 int error2;
1300
1301 error = ext4_xattr_set_handle(handle, inode, name_index, name,
1302 value, value_len, flags);
1303 error2 = ext4_journal_stop(handle);
1304 if (error == -ENOSPC &&
1305 ext4_should_retry_alloc(inode->i_sb, &retries))
1306 goto retry;
1307 if (error == 0)
1308 error = error2;
1309 }
1310
1311 return error;
1312}
1313
1314/*
1315 * Shift the EA entries in the inode to create space for the increased
1316 * i_extra_isize.
1317 */
1318static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
1319 int value_offs_shift, void *to,
1320 void *from, size_t n, int blocksize)
1321{
1322 struct ext4_xattr_entry *last = entry;
1323 int new_offs;
1324
1325 /* Adjust the value offsets of the entries */
1326 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1327 if (!last->e_value_block && last->e_value_size) {
1328 new_offs = le16_to_cpu(last->e_value_offs) +
1329 value_offs_shift;
1330 BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
1331 > blocksize);
1332 last->e_value_offs = cpu_to_le16(new_offs);
1333 }
1334 }
1335 /* Shift the entries by n bytes */
1336 memmove(to, from, n);
1337}
1338
1339/*
1340 * Expand an inode by new_extra_isize bytes when EAs are present.
1341 * Returns 0 on success or negative error number on failure.
1342 */
1343int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1344 struct ext4_inode *raw_inode, handle_t *handle)
1345{
1346 struct ext4_xattr_ibody_header *header;
1347 struct ext4_xattr_entry *entry, *last, *first;
1348 struct buffer_head *bh = NULL;
1349 struct ext4_xattr_ibody_find *is = NULL;
1350 struct ext4_xattr_block_find *bs = NULL;
1351 char *buffer = NULL, *b_entry_name = NULL;
1352 size_t min_offs, free;
1353 int total_ino;
1354 void *base, *start, *end;
1355 int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
1356 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
1357
1358 down_write(&EXT4_I(inode)->xattr_sem);
1359retry:
1360 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
1361 up_write(&EXT4_I(inode)->xattr_sem);
1362 return 0;
1363 }
1364
1365 header = IHDR(inode, raw_inode);
1366 entry = IFIRST(header);
1367
1368 /*
1369 * Check if enough free space is available in the inode to shift the
1370 * entries ahead by new_extra_isize.
1371 */
1372
1373 base = start = entry;
1374 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
1375 min_offs = end - base;
1376 last = entry;
1377 total_ino = sizeof(struct ext4_xattr_ibody_header);
1378
1379 error = xattr_check_inode(inode, header, end);
1380 if (error)
1381 goto cleanup;
1382
1383 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
1384 if (free >= new_extra_isize) {
1385 entry = IFIRST(header);
1386 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
1387 - new_extra_isize, (void *)raw_inode +
1388 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
1389 (void *)header, total_ino,
1390 inode->i_sb->s_blocksize);
1391 EXT4_I(inode)->i_extra_isize = new_extra_isize;
1392 error = 0;
1393 goto cleanup;
1394 }
1395
1396 /*
1397 * Enough free space isn't available in the inode, check if
1398 * EA block can hold new_extra_isize bytes.
1399 */
1400 if (EXT4_I(inode)->i_file_acl) {
1401 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1402 error = -EIO;
1403 if (!bh)
1404 goto cleanup;
1405 if (ext4_xattr_check_block(inode, bh)) {
1406 EXT4_ERROR_INODE(inode, "bad block %llu",
1407 EXT4_I(inode)->i_file_acl);
1408 error = -EFSCORRUPTED;
1409 goto cleanup;
1410 }
1411 base = BHDR(bh);
1412 first = BFIRST(bh);
1413 end = bh->b_data + bh->b_size;
1414 min_offs = end - base;
1415 free = ext4_xattr_free_space(first, &min_offs, base, NULL);
1416 if (free < new_extra_isize) {
1417 if (!tried_min_extra_isize && s_min_extra_isize) {
1418 tried_min_extra_isize++;
1419 new_extra_isize = s_min_extra_isize;
1420 brelse(bh);
1421 goto retry;
1422 }
1423 error = -1;
1424 goto cleanup;
1425 }
1426 } else {
1427 free = inode->i_sb->s_blocksize;
1428 }
1429
1430 while (new_extra_isize > 0) {
1431 size_t offs, size, entry_size;
1432 struct ext4_xattr_entry *small_entry = NULL;
1433 struct ext4_xattr_info i = {
1434 .value = NULL,
1435 .value_len = 0,
1436 };
1437 unsigned int total_size; /* EA entry size + value size */
1438 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
1439 unsigned int min_total_size = ~0U;
1440
1441 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
1442 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
1443 if (!is || !bs) {
1444 error = -ENOMEM;
1445 goto cleanup;
1446 }
1447
1448 is->s.not_found = -ENODATA;
1449 bs->s.not_found = -ENODATA;
1450 is->iloc.bh = NULL;
1451 bs->bh = NULL;
1452
1453 last = IFIRST(header);
1454 /* Find the entry best suited to be pushed into EA block */
1455 entry = NULL;
1456 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1457 total_size =
1458 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
1459 EXT4_XATTR_LEN(last->e_name_len);
1460 if (total_size <= free && total_size < min_total_size) {
1461 if (total_size < new_extra_isize) {
1462 small_entry = last;
1463 } else {
1464 entry = last;
1465 min_total_size = total_size;
1466 }
1467 }
1468 }
1469
1470 if (entry == NULL) {
1471 if (small_entry) {
1472 entry = small_entry;
1473 } else {
1474 if (!tried_min_extra_isize &&
1475 s_min_extra_isize) {
1476 tried_min_extra_isize++;
1477 new_extra_isize = s_min_extra_isize;
1478 kfree(is); is = NULL;
1479 kfree(bs); bs = NULL;
1480 brelse(bh);
1481 goto retry;
1482 }
1483 error = -1;
1484 goto cleanup;
1485 }
1486 }
1487 offs = le16_to_cpu(entry->e_value_offs);
1488 size = le32_to_cpu(entry->e_value_size);
1489 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
1490 i.name_index = entry->e_name_index,
1491 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
1492 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
1493 if (!buffer || !b_entry_name) {
1494 error = -ENOMEM;
1495 goto cleanup;
1496 }
1497 /* Save the entry name and the entry value */
1498 memcpy(buffer, (void *)IFIRST(header) + offs,
1499 EXT4_XATTR_SIZE(size));
1500 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
1501 b_entry_name[entry->e_name_len] = '\0';
1502 i.name = b_entry_name;
1503
1504 error = ext4_get_inode_loc(inode, &is->iloc);
1505 if (error)
1506 goto cleanup;
1507
1508 error = ext4_xattr_ibody_find(inode, &i, is);
1509 if (error)
1510 goto cleanup;
1511
1512 /* Remove the chosen entry from the inode */
1513 error = ext4_xattr_ibody_set(handle, inode, &i, is);
1514 if (error)
1515 goto cleanup;
1516
1517 entry = IFIRST(header);
1518 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
1519 shift_bytes = new_extra_isize;
1520 else
1521 shift_bytes = entry_size + size;
1522 /* Adjust the offsets and shift the remaining entries ahead */
1523 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
1524 shift_bytes, (void *)raw_inode +
1525 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
1526 (void *)header, total_ino - entry_size,
1527 inode->i_sb->s_blocksize);
1528
1529 extra_isize += shift_bytes;
1530 new_extra_isize -= shift_bytes;
1531 EXT4_I(inode)->i_extra_isize = extra_isize;
1532
1533 i.name = b_entry_name;
1534 i.value = buffer;
1535 i.value_len = size;
1536 error = ext4_xattr_block_find(inode, &i, bs);
1537 if (error)
1538 goto cleanup;
1539
1540 /* Add entry which was removed from the inode into the block */
1541 error = ext4_xattr_block_set(handle, inode, &i, bs);
1542 if (error)
1543 goto cleanup;
1544 kfree(b_entry_name);
1545 kfree(buffer);
1546 b_entry_name = NULL;
1547 buffer = NULL;
1548 brelse(is->iloc.bh);
1549 kfree(is);
1550 kfree(bs);
1551 }
1552 brelse(bh);
1553 up_write(&EXT4_I(inode)->xattr_sem);
1554 return 0;
1555
1556cleanup:
1557 kfree(b_entry_name);
1558 kfree(buffer);
1559 if (is)
1560 brelse(is->iloc.bh);
1561 kfree(is);
1562 kfree(bs);
1563 brelse(bh);
1564 up_write(&EXT4_I(inode)->xattr_sem);
1565 return error;
1566}
1567
1568
1569
1570/*
1571 * ext4_xattr_delete_inode()
1572 *
1573 * Free extended attribute resources associated with this inode. This
1574 * is called immediately before an inode is freed. We have exclusive
1575 * access to the inode.
1576 */
1577void
1578ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
1579{
1580 struct buffer_head *bh = NULL;
1581
1582 if (!EXT4_I(inode)->i_file_acl)
1583 goto cleanup;
1584 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
1585 if (!bh) {
1586 EXT4_ERROR_INODE(inode, "block %llu read error",
1587 EXT4_I(inode)->i_file_acl);
1588 goto cleanup;
1589 }
1590 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
1591 BHDR(bh)->h_blocks != cpu_to_le32(1)) {
1592 EXT4_ERROR_INODE(inode, "bad block %llu",
1593 EXT4_I(inode)->i_file_acl);
1594 goto cleanup;
1595 }
1596 ext4_xattr_release_block(handle, inode, bh);
1597 EXT4_I(inode)->i_file_acl = 0;
1598
1599cleanup:
1600 brelse(bh);
1601}
1602
1603/*
1604 * ext4_xattr_cache_insert()
1605 *
1606 * Create a new entry in the extended attribute cache, and insert
1607 * it unless such an entry is already in the cache.
1608 *
1609 * Returns 0, or a negative error number on failure.
1610 */
1611static void
1612ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
1613{
1614 struct ext4_xattr_header *header = BHDR(bh);
1615 __u32 hash = le32_to_cpu(header->h_hash);
1616 int reusable = le32_to_cpu(header->h_refcount) <
1617 EXT4_XATTR_REFCOUNT_MAX;
1618 int error;
1619
1620 error = mb_cache_entry_create(ext4_mb_cache, GFP_NOFS, hash,
1621 bh->b_blocknr, reusable);
1622 if (error) {
1623 if (error == -EBUSY)
1624 ea_bdebug(bh, "already in cache");
1625 } else
1626 ea_bdebug(bh, "inserting [%x]", (int)hash);
1627}
1628
1629/*
1630 * ext4_xattr_cmp()
1631 *
1632 * Compare two extended attribute blocks for equality.
1633 *
1634 * Returns 0 if the blocks are equal, 1 if they differ, and
1635 * a negative error number on errors.
1636 */
1637static int
1638ext4_xattr_cmp(struct ext4_xattr_header *header1,
1639 struct ext4_xattr_header *header2)
1640{
1641 struct ext4_xattr_entry *entry1, *entry2;
1642
1643 entry1 = ENTRY(header1+1);
1644 entry2 = ENTRY(header2+1);
1645 while (!IS_LAST_ENTRY(entry1)) {
1646 if (IS_LAST_ENTRY(entry2))
1647 return 1;
1648 if (entry1->e_hash != entry2->e_hash ||
1649 entry1->e_name_index != entry2->e_name_index ||
1650 entry1->e_name_len != entry2->e_name_len ||
1651 entry1->e_value_size != entry2->e_value_size ||
1652 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
1653 return 1;
1654 if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
1655 return -EFSCORRUPTED;
1656 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
1657 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
1658 le32_to_cpu(entry1->e_value_size)))
1659 return 1;
1660
1661 entry1 = EXT4_XATTR_NEXT(entry1);
1662 entry2 = EXT4_XATTR_NEXT(entry2);
1663 }
1664 if (!IS_LAST_ENTRY(entry2))
1665 return 1;
1666 return 0;
1667}
1668
1669/*
1670 * ext4_xattr_cache_find()
1671 *
1672 * Find an identical extended attribute block.
1673 *
1674 * Returns a pointer to the block found, or NULL if such a block was
1675 * not found or an error occurred.
1676 */
1677static struct buffer_head *
1678ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
1679 struct mb_cache_entry **pce)
1680{
1681 __u32 hash = le32_to_cpu(header->h_hash);
1682 struct mb_cache_entry *ce;
1683 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
1684
1685 if (!header->h_hash)
1686 return NULL; /* never share */
1687 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
1688 ce = mb_cache_entry_find_first(ext4_mb_cache, hash);
1689 while (ce) {
1690 struct buffer_head *bh;
1691
1692 bh = sb_bread(inode->i_sb, ce->e_block);
1693 if (!bh) {
1694 EXT4_ERROR_INODE(inode, "block %lu read error",
1695 (unsigned long) ce->e_block);
1696 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
1697 *pce = ce;
1698 return bh;
1699 }
1700 brelse(bh);
1701 ce = mb_cache_entry_find_next(ext4_mb_cache, ce);
1702 }
1703 return NULL;
1704}
1705
1706#define NAME_HASH_SHIFT 5
1707#define VALUE_HASH_SHIFT 16
1708
1709/*
1710 * ext4_xattr_hash_entry()
1711 *
1712 * Compute the hash of an extended attribute.
1713 */
1714static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
1715 struct ext4_xattr_entry *entry)
1716{
1717 __u32 hash = 0;
1718 char *name = entry->e_name;
1719 int n;
1720
1721 for (n = 0; n < entry->e_name_len; n++) {
1722 hash = (hash << NAME_HASH_SHIFT) ^
1723 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
1724 *name++;
1725 }
1726
1727 if (entry->e_value_block == 0 && entry->e_value_size != 0) {
1728 __le32 *value = (__le32 *)((char *)header +
1729 le16_to_cpu(entry->e_value_offs));
1730 for (n = (le32_to_cpu(entry->e_value_size) +
1731 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
1732 hash = (hash << VALUE_HASH_SHIFT) ^
1733 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
1734 le32_to_cpu(*value++);
1735 }
1736 }
1737 entry->e_hash = cpu_to_le32(hash);
1738}
1739
1740#undef NAME_HASH_SHIFT
1741#undef VALUE_HASH_SHIFT
1742
1743#define BLOCK_HASH_SHIFT 16
1744
1745/*
1746 * ext4_xattr_rehash()
1747 *
1748 * Re-compute the extended attribute hash value after an entry has changed.
1749 */
1750static void ext4_xattr_rehash(struct ext4_xattr_header *header,
1751 struct ext4_xattr_entry *entry)
1752{
1753 struct ext4_xattr_entry *here;
1754 __u32 hash = 0;
1755
1756 ext4_xattr_hash_entry(header, entry);
1757 here = ENTRY(header+1);
1758 while (!IS_LAST_ENTRY(here)) {
1759 if (!here->e_hash) {
1760 /* Block is not shared if an entry's hash value == 0 */
1761 hash = 0;
1762 break;
1763 }
1764 hash = (hash << BLOCK_HASH_SHIFT) ^
1765 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
1766 le32_to_cpu(here->e_hash);
1767 here = EXT4_XATTR_NEXT(here);
1768 }
1769 header->h_hash = cpu_to_le32(hash);
1770}
1771
1772#undef BLOCK_HASH_SHIFT
1773
1774#define HASH_BUCKET_BITS 10
1775
1776struct mb_cache *
1777ext4_xattr_create_cache(void)
1778{
1779 return mb_cache_create(HASH_BUCKET_BITS);
1780}
1781
1782void ext4_xattr_destroy_cache(struct mb_cache *cache)
1783{
1784 if (cache)
1785 mb_cache_destroy(cache);
1786}
1787
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/ext4/xattr.c
4 *
5 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
6 *
7 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
8 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
9 * Extended attributes for symlinks and special files added per
10 * suggestion of Luka Renko <luka.renko@hermes.si>.
11 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
12 * Red Hat Inc.
13 * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
14 * and Andreas Gruenbacher <agruen@suse.de>.
15 */
16
17/*
18 * Extended attributes are stored directly in inodes (on file systems with
19 * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
20 * field contains the block number if an inode uses an additional block. All
21 * attributes must fit in the inode and one additional block. Blocks that
22 * contain the identical set of attributes may be shared among several inodes.
23 * Identical blocks are detected by keeping a cache of blocks that have
24 * recently been accessed.
25 *
26 * The attributes in inodes and on blocks have a different header; the entries
27 * are stored in the same format:
28 *
29 * +------------------+
30 * | header |
31 * | entry 1 | |
32 * | entry 2 | | growing downwards
33 * | entry 3 | v
34 * | four null bytes |
35 * | . . . |
36 * | value 1 | ^
37 * | value 3 | | growing upwards
38 * | value 2 | |
39 * +------------------+
40 *
41 * The header is followed by multiple entry descriptors. In disk blocks, the
42 * entry descriptors are kept sorted. In inodes, they are unsorted. The
43 * attribute values are aligned to the end of the block in no specific order.
44 *
45 * Locking strategy
46 * ----------------
47 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
48 * EA blocks are only changed if they are exclusive to an inode, so
49 * holding xattr_sem also means that nothing but the EA block's reference
50 * count can change. Multiple writers to the same block are synchronized
51 * by the buffer lock.
52 */
53
54#include <linux/init.h>
55#include <linux/fs.h>
56#include <linux/slab.h>
57#include <linux/mbcache.h>
58#include <linux/quotaops.h>
59#include <linux/iversion.h>
60#include "ext4_jbd2.h"
61#include "ext4.h"
62#include "xattr.h"
63#include "acl.h"
64
65#ifdef EXT4_XATTR_DEBUG
66# define ea_idebug(inode, fmt, ...) \
67 printk(KERN_DEBUG "inode %s:%lu: " fmt "\n", \
68 inode->i_sb->s_id, inode->i_ino, ##__VA_ARGS__)
69# define ea_bdebug(bh, fmt, ...) \
70 printk(KERN_DEBUG "block %pg:%lu: " fmt "\n", \
71 bh->b_bdev, (unsigned long)bh->b_blocknr, ##__VA_ARGS__)
72#else
73# define ea_idebug(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
74# define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
75#endif
76
77static void ext4_xattr_block_cache_insert(struct mb_cache *,
78 struct buffer_head *);
79static struct buffer_head *
80ext4_xattr_block_cache_find(struct inode *, struct ext4_xattr_header *,
81 struct mb_cache_entry **);
82static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
83 size_t value_count);
84static void ext4_xattr_rehash(struct ext4_xattr_header *);
85
86static const struct xattr_handler * const ext4_xattr_handler_map[] = {
87 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
88#ifdef CONFIG_EXT4_FS_POSIX_ACL
89 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
90 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
91#endif
92 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
93#ifdef CONFIG_EXT4_FS_SECURITY
94 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
95#endif
96 [EXT4_XATTR_INDEX_HURD] = &ext4_xattr_hurd_handler,
97};
98
99const struct xattr_handler *ext4_xattr_handlers[] = {
100 &ext4_xattr_user_handler,
101 &ext4_xattr_trusted_handler,
102#ifdef CONFIG_EXT4_FS_POSIX_ACL
103 &posix_acl_access_xattr_handler,
104 &posix_acl_default_xattr_handler,
105#endif
106#ifdef CONFIG_EXT4_FS_SECURITY
107 &ext4_xattr_security_handler,
108#endif
109 &ext4_xattr_hurd_handler,
110 NULL
111};
112
113#define EA_BLOCK_CACHE(inode) (((struct ext4_sb_info *) \
114 inode->i_sb->s_fs_info)->s_ea_block_cache)
115
116#define EA_INODE_CACHE(inode) (((struct ext4_sb_info *) \
117 inode->i_sb->s_fs_info)->s_ea_inode_cache)
118
119static int
120ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
121 struct inode *inode);
122
123#ifdef CONFIG_LOCKDEP
124void ext4_xattr_inode_set_class(struct inode *ea_inode)
125{
126 lockdep_set_subclass(&ea_inode->i_rwsem, 1);
127}
128#endif
129
130static __le32 ext4_xattr_block_csum(struct inode *inode,
131 sector_t block_nr,
132 struct ext4_xattr_header *hdr)
133{
134 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
135 __u32 csum;
136 __le64 dsk_block_nr = cpu_to_le64(block_nr);
137 __u32 dummy_csum = 0;
138 int offset = offsetof(struct ext4_xattr_header, h_checksum);
139
140 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr,
141 sizeof(dsk_block_nr));
142 csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset);
143 csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum));
144 offset += sizeof(dummy_csum);
145 csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset,
146 EXT4_BLOCK_SIZE(inode->i_sb) - offset);
147
148 return cpu_to_le32(csum);
149}
150
151static int ext4_xattr_block_csum_verify(struct inode *inode,
152 struct buffer_head *bh)
153{
154 struct ext4_xattr_header *hdr = BHDR(bh);
155 int ret = 1;
156
157 if (ext4_has_metadata_csum(inode->i_sb)) {
158 lock_buffer(bh);
159 ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
160 bh->b_blocknr, hdr));
161 unlock_buffer(bh);
162 }
163 return ret;
164}
165
166static void ext4_xattr_block_csum_set(struct inode *inode,
167 struct buffer_head *bh)
168{
169 if (ext4_has_metadata_csum(inode->i_sb))
170 BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
171 bh->b_blocknr, BHDR(bh));
172}
173
174static inline const struct xattr_handler *
175ext4_xattr_handler(int name_index)
176{
177 const struct xattr_handler *handler = NULL;
178
179 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
180 handler = ext4_xattr_handler_map[name_index];
181 return handler;
182}
183
184static int
185ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end,
186 void *value_start)
187{
188 struct ext4_xattr_entry *e = entry;
189
190 /* Find the end of the names list */
191 while (!IS_LAST_ENTRY(e)) {
192 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
193 if ((void *)next >= end)
194 return -EFSCORRUPTED;
195 if (strnlen(e->e_name, e->e_name_len) != e->e_name_len)
196 return -EFSCORRUPTED;
197 e = next;
198 }
199
200 /* Check the values */
201 while (!IS_LAST_ENTRY(entry)) {
202 u32 size = le32_to_cpu(entry->e_value_size);
203
204 if (size > EXT4_XATTR_SIZE_MAX)
205 return -EFSCORRUPTED;
206
207 if (size != 0 && entry->e_value_inum == 0) {
208 u16 offs = le16_to_cpu(entry->e_value_offs);
209 void *value;
210
211 /*
212 * The value cannot overlap the names, and the value
213 * with padding cannot extend beyond 'end'. Check both
214 * the padded and unpadded sizes, since the size may
215 * overflow to 0 when adding padding.
216 */
217 if (offs > end - value_start)
218 return -EFSCORRUPTED;
219 value = value_start + offs;
220 if (value < (void *)e + sizeof(u32) ||
221 size > end - value ||
222 EXT4_XATTR_SIZE(size) > end - value)
223 return -EFSCORRUPTED;
224 }
225 entry = EXT4_XATTR_NEXT(entry);
226 }
227
228 return 0;
229}
230
231static inline int
232__ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh,
233 const char *function, unsigned int line)
234{
235 int error = -EFSCORRUPTED;
236
237 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
238 BHDR(bh)->h_blocks != cpu_to_le32(1))
239 goto errout;
240 if (buffer_verified(bh))
241 return 0;
242
243 error = -EFSBADCRC;
244 if (!ext4_xattr_block_csum_verify(inode, bh))
245 goto errout;
246 error = ext4_xattr_check_entries(BFIRST(bh), bh->b_data + bh->b_size,
247 bh->b_data);
248errout:
249 if (error)
250 __ext4_error_inode(inode, function, line, 0, -error,
251 "corrupted xattr block %llu",
252 (unsigned long long) bh->b_blocknr);
253 else
254 set_buffer_verified(bh);
255 return error;
256}
257
258#define ext4_xattr_check_block(inode, bh) \
259 __ext4_xattr_check_block((inode), (bh), __func__, __LINE__)
260
261
262static int
263__xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header,
264 void *end, const char *function, unsigned int line)
265{
266 int error = -EFSCORRUPTED;
267
268 if (end - (void *)header < sizeof(*header) + sizeof(u32) ||
269 (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)))
270 goto errout;
271 error = ext4_xattr_check_entries(IFIRST(header), end, IFIRST(header));
272errout:
273 if (error)
274 __ext4_error_inode(inode, function, line, 0, -error,
275 "corrupted in-inode xattr");
276 return error;
277}
278
279#define xattr_check_inode(inode, header, end) \
280 __xattr_check_inode((inode), (header), (end), __func__, __LINE__)
281
282static int
283xattr_find_entry(struct inode *inode, struct ext4_xattr_entry **pentry,
284 void *end, int name_index, const char *name, int sorted)
285{
286 struct ext4_xattr_entry *entry, *next;
287 size_t name_len;
288 int cmp = 1;
289
290 if (name == NULL)
291 return -EINVAL;
292 name_len = strlen(name);
293 for (entry = *pentry; !IS_LAST_ENTRY(entry); entry = next) {
294 next = EXT4_XATTR_NEXT(entry);
295 if ((void *) next >= end) {
296 EXT4_ERROR_INODE(inode, "corrupted xattr entries");
297 return -EFSCORRUPTED;
298 }
299 cmp = name_index - entry->e_name_index;
300 if (!cmp)
301 cmp = name_len - entry->e_name_len;
302 if (!cmp)
303 cmp = memcmp(name, entry->e_name, name_len);
304 if (cmp <= 0 && (sorted || cmp == 0))
305 break;
306 }
307 *pentry = entry;
308 return cmp ? -ENODATA : 0;
309}
310
311static u32
312ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
313{
314 return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
315}
316
317static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
318{
319 return ((u64)ea_inode->i_ctime.tv_sec << 32) |
320 (u32) inode_peek_iversion_raw(ea_inode);
321}
322
323static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
324{
325 ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
326 inode_set_iversion_raw(ea_inode, ref_count & 0xffffffff);
327}
328
329static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
330{
331 return (u32)ea_inode->i_atime.tv_sec;
332}
333
334static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
335{
336 ea_inode->i_atime.tv_sec = hash;
337}
338
339/*
340 * Read the EA value from an inode.
341 */
342static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
343{
344 int blocksize = 1 << ea_inode->i_blkbits;
345 int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits;
346 int tail_size = (size % blocksize) ?: blocksize;
347 struct buffer_head *bhs_inline[8];
348 struct buffer_head **bhs = bhs_inline;
349 int i, ret;
350
351 if (bh_count > ARRAY_SIZE(bhs_inline)) {
352 bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS);
353 if (!bhs)
354 return -ENOMEM;
355 }
356
357 ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count,
358 true /* wait */, bhs);
359 if (ret)
360 goto free_bhs;
361
362 for (i = 0; i < bh_count; i++) {
363 /* There shouldn't be any holes in ea_inode. */
364 if (!bhs[i]) {
365 ret = -EFSCORRUPTED;
366 goto put_bhs;
367 }
368 memcpy((char *)buf + blocksize * i, bhs[i]->b_data,
369 i < bh_count - 1 ? blocksize : tail_size);
370 }
371 ret = 0;
372put_bhs:
373 for (i = 0; i < bh_count; i++)
374 brelse(bhs[i]);
375free_bhs:
376 if (bhs != bhs_inline)
377 kfree(bhs);
378 return ret;
379}
380
381#define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec)
382
383static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
384 u32 ea_inode_hash, struct inode **ea_inode)
385{
386 struct inode *inode;
387 int err;
388
389 inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_NORMAL);
390 if (IS_ERR(inode)) {
391 err = PTR_ERR(inode);
392 ext4_error(parent->i_sb,
393 "error while reading EA inode %lu err=%d", ea_ino,
394 err);
395 return err;
396 }
397
398 if (is_bad_inode(inode)) {
399 ext4_error(parent->i_sb,
400 "error while reading EA inode %lu is_bad_inode",
401 ea_ino);
402 err = -EIO;
403 goto error;
404 }
405
406 if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
407 ext4_error(parent->i_sb,
408 "EA inode %lu does not have EXT4_EA_INODE_FL flag",
409 ea_ino);
410 err = -EINVAL;
411 goto error;
412 }
413
414 ext4_xattr_inode_set_class(inode);
415
416 /*
417 * Check whether this is an old Lustre-style xattr inode. Lustre
418 * implementation does not have hash validation, rather it has a
419 * backpointer from ea_inode to the parent inode.
420 */
421 if (ea_inode_hash != ext4_xattr_inode_get_hash(inode) &&
422 EXT4_XATTR_INODE_GET_PARENT(inode) == parent->i_ino &&
423 inode->i_generation == parent->i_generation) {
424 ext4_set_inode_state(inode, EXT4_STATE_LUSTRE_EA_INODE);
425 ext4_xattr_inode_set_ref(inode, 1);
426 } else {
427 inode_lock(inode);
428 inode->i_flags |= S_NOQUOTA;
429 inode_unlock(inode);
430 }
431
432 *ea_inode = inode;
433 return 0;
434error:
435 iput(inode);
436 return err;
437}
438
439static int
440ext4_xattr_inode_verify_hashes(struct inode *ea_inode,
441 struct ext4_xattr_entry *entry, void *buffer,
442 size_t size)
443{
444 u32 hash;
445
446 /* Verify stored hash matches calculated hash. */
447 hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
448 if (hash != ext4_xattr_inode_get_hash(ea_inode))
449 return -EFSCORRUPTED;
450
451 if (entry) {
452 __le32 e_hash, tmp_data;
453
454 /* Verify entry hash. */
455 tmp_data = cpu_to_le32(hash);
456 e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len,
457 &tmp_data, 1);
458 if (e_hash != entry->e_hash)
459 return -EFSCORRUPTED;
460 }
461 return 0;
462}
463
464/*
465 * Read xattr value from the EA inode.
466 */
467static int
468ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry,
469 void *buffer, size_t size)
470{
471 struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
472 struct inode *ea_inode;
473 int err;
474
475 err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum),
476 le32_to_cpu(entry->e_hash), &ea_inode);
477 if (err) {
478 ea_inode = NULL;
479 goto out;
480 }
481
482 if (i_size_read(ea_inode) != size) {
483 ext4_warning_inode(ea_inode,
484 "ea_inode file size=%llu entry size=%zu",
485 i_size_read(ea_inode), size);
486 err = -EFSCORRUPTED;
487 goto out;
488 }
489
490 err = ext4_xattr_inode_read(ea_inode, buffer, size);
491 if (err)
492 goto out;
493
494 if (!ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) {
495 err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer,
496 size);
497 if (err) {
498 ext4_warning_inode(ea_inode,
499 "EA inode hash validation failed");
500 goto out;
501 }
502
503 if (ea_inode_cache)
504 mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
505 ext4_xattr_inode_get_hash(ea_inode),
506 ea_inode->i_ino, true /* reusable */);
507 }
508out:
509 iput(ea_inode);
510 return err;
511}
512
513static int
514ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
515 void *buffer, size_t buffer_size)
516{
517 struct buffer_head *bh = NULL;
518 struct ext4_xattr_entry *entry;
519 size_t size;
520 void *end;
521 int error;
522 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
523
524 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
525 name_index, name, buffer, (long)buffer_size);
526
527 if (!EXT4_I(inode)->i_file_acl)
528 return -ENODATA;
529 ea_idebug(inode, "reading block %llu",
530 (unsigned long long)EXT4_I(inode)->i_file_acl);
531 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
532 if (IS_ERR(bh))
533 return PTR_ERR(bh);
534 ea_bdebug(bh, "b_count=%d, refcount=%d",
535 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
536 error = ext4_xattr_check_block(inode, bh);
537 if (error)
538 goto cleanup;
539 ext4_xattr_block_cache_insert(ea_block_cache, bh);
540 entry = BFIRST(bh);
541 end = bh->b_data + bh->b_size;
542 error = xattr_find_entry(inode, &entry, end, name_index, name, 1);
543 if (error)
544 goto cleanup;
545 size = le32_to_cpu(entry->e_value_size);
546 error = -ERANGE;
547 if (unlikely(size > EXT4_XATTR_SIZE_MAX))
548 goto cleanup;
549 if (buffer) {
550 if (size > buffer_size)
551 goto cleanup;
552 if (entry->e_value_inum) {
553 error = ext4_xattr_inode_get(inode, entry, buffer,
554 size);
555 if (error)
556 goto cleanup;
557 } else {
558 u16 offset = le16_to_cpu(entry->e_value_offs);
559 void *p = bh->b_data + offset;
560
561 if (unlikely(p + size > end))
562 goto cleanup;
563 memcpy(buffer, p, size);
564 }
565 }
566 error = size;
567
568cleanup:
569 brelse(bh);
570 return error;
571}
572
573int
574ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
575 void *buffer, size_t buffer_size)
576{
577 struct ext4_xattr_ibody_header *header;
578 struct ext4_xattr_entry *entry;
579 struct ext4_inode *raw_inode;
580 struct ext4_iloc iloc;
581 size_t size;
582 void *end;
583 int error;
584
585 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
586 return -ENODATA;
587 error = ext4_get_inode_loc(inode, &iloc);
588 if (error)
589 return error;
590 raw_inode = ext4_raw_inode(&iloc);
591 header = IHDR(inode, raw_inode);
592 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
593 error = xattr_check_inode(inode, header, end);
594 if (error)
595 goto cleanup;
596 entry = IFIRST(header);
597 error = xattr_find_entry(inode, &entry, end, name_index, name, 0);
598 if (error)
599 goto cleanup;
600 size = le32_to_cpu(entry->e_value_size);
601 error = -ERANGE;
602 if (unlikely(size > EXT4_XATTR_SIZE_MAX))
603 goto cleanup;
604 if (buffer) {
605 if (size > buffer_size)
606 goto cleanup;
607 if (entry->e_value_inum) {
608 error = ext4_xattr_inode_get(inode, entry, buffer,
609 size);
610 if (error)
611 goto cleanup;
612 } else {
613 u16 offset = le16_to_cpu(entry->e_value_offs);
614 void *p = (void *)IFIRST(header) + offset;
615
616 if (unlikely(p + size > end))
617 goto cleanup;
618 memcpy(buffer, p, size);
619 }
620 }
621 error = size;
622
623cleanup:
624 brelse(iloc.bh);
625 return error;
626}
627
628/*
629 * ext4_xattr_get()
630 *
631 * Copy an extended attribute into the buffer
632 * provided, or compute the buffer size required.
633 * Buffer is NULL to compute the size of the buffer required.
634 *
635 * Returns a negative error number on failure, or the number of bytes
636 * used / required on success.
637 */
638int
639ext4_xattr_get(struct inode *inode, int name_index, const char *name,
640 void *buffer, size_t buffer_size)
641{
642 int error;
643
644 if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
645 return -EIO;
646
647 if (strlen(name) > 255)
648 return -ERANGE;
649
650 down_read(&EXT4_I(inode)->xattr_sem);
651 error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
652 buffer_size);
653 if (error == -ENODATA)
654 error = ext4_xattr_block_get(inode, name_index, name, buffer,
655 buffer_size);
656 up_read(&EXT4_I(inode)->xattr_sem);
657 return error;
658}
659
660static int
661ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry,
662 char *buffer, size_t buffer_size)
663{
664 size_t rest = buffer_size;
665
666 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
667 const struct xattr_handler *handler =
668 ext4_xattr_handler(entry->e_name_index);
669
670 if (handler && (!handler->list || handler->list(dentry))) {
671 const char *prefix = handler->prefix ?: handler->name;
672 size_t prefix_len = strlen(prefix);
673 size_t size = prefix_len + entry->e_name_len + 1;
674
675 if (buffer) {
676 if (size > rest)
677 return -ERANGE;
678 memcpy(buffer, prefix, prefix_len);
679 buffer += prefix_len;
680 memcpy(buffer, entry->e_name, entry->e_name_len);
681 buffer += entry->e_name_len;
682 *buffer++ = 0;
683 }
684 rest -= size;
685 }
686 }
687 return buffer_size - rest; /* total size */
688}
689
690static int
691ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
692{
693 struct inode *inode = d_inode(dentry);
694 struct buffer_head *bh = NULL;
695 int error;
696
697 ea_idebug(inode, "buffer=%p, buffer_size=%ld",
698 buffer, (long)buffer_size);
699
700 if (!EXT4_I(inode)->i_file_acl)
701 return 0;
702 ea_idebug(inode, "reading block %llu",
703 (unsigned long long)EXT4_I(inode)->i_file_acl);
704 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
705 if (IS_ERR(bh))
706 return PTR_ERR(bh);
707 ea_bdebug(bh, "b_count=%d, refcount=%d",
708 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
709 error = ext4_xattr_check_block(inode, bh);
710 if (error)
711 goto cleanup;
712 ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh);
713 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer,
714 buffer_size);
715cleanup:
716 brelse(bh);
717 return error;
718}
719
720static int
721ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size)
722{
723 struct inode *inode = d_inode(dentry);
724 struct ext4_xattr_ibody_header *header;
725 struct ext4_inode *raw_inode;
726 struct ext4_iloc iloc;
727 void *end;
728 int error;
729
730 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
731 return 0;
732 error = ext4_get_inode_loc(inode, &iloc);
733 if (error)
734 return error;
735 raw_inode = ext4_raw_inode(&iloc);
736 header = IHDR(inode, raw_inode);
737 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
738 error = xattr_check_inode(inode, header, end);
739 if (error)
740 goto cleanup;
741 error = ext4_xattr_list_entries(dentry, IFIRST(header),
742 buffer, buffer_size);
743
744cleanup:
745 brelse(iloc.bh);
746 return error;
747}
748
749/*
750 * Inode operation listxattr()
751 *
752 * d_inode(dentry)->i_rwsem: don't care
753 *
754 * Copy a list of attribute names into the buffer
755 * provided, or compute the buffer size required.
756 * Buffer is NULL to compute the size of the buffer required.
757 *
758 * Returns a negative error number on failure, or the number of bytes
759 * used / required on success.
760 */
761ssize_t
762ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
763{
764 int ret, ret2;
765
766 down_read(&EXT4_I(d_inode(dentry))->xattr_sem);
767 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size);
768 if (ret < 0)
769 goto errout;
770 if (buffer) {
771 buffer += ret;
772 buffer_size -= ret;
773 }
774 ret = ext4_xattr_block_list(dentry, buffer, buffer_size);
775 if (ret < 0)
776 goto errout;
777 ret += ret2;
778errout:
779 up_read(&EXT4_I(d_inode(dentry))->xattr_sem);
780 return ret;
781}
782
783/*
784 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
785 * not set, set it.
786 */
787static void ext4_xattr_update_super_block(handle_t *handle,
788 struct super_block *sb)
789{
790 if (ext4_has_feature_xattr(sb))
791 return;
792
793 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
794 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
795 lock_buffer(EXT4_SB(sb)->s_sbh);
796 ext4_set_feature_xattr(sb);
797 ext4_superblock_csum_set(sb);
798 unlock_buffer(EXT4_SB(sb)->s_sbh);
799 ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
800 }
801}
802
803int ext4_get_inode_usage(struct inode *inode, qsize_t *usage)
804{
805 struct ext4_iloc iloc = { .bh = NULL };
806 struct buffer_head *bh = NULL;
807 struct ext4_inode *raw_inode;
808 struct ext4_xattr_ibody_header *header;
809 struct ext4_xattr_entry *entry;
810 qsize_t ea_inode_refs = 0;
811 void *end;
812 int ret;
813
814 lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
815
816 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
817 ret = ext4_get_inode_loc(inode, &iloc);
818 if (ret)
819 goto out;
820 raw_inode = ext4_raw_inode(&iloc);
821 header = IHDR(inode, raw_inode);
822 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
823 ret = xattr_check_inode(inode, header, end);
824 if (ret)
825 goto out;
826
827 for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
828 entry = EXT4_XATTR_NEXT(entry))
829 if (entry->e_value_inum)
830 ea_inode_refs++;
831 }
832
833 if (EXT4_I(inode)->i_file_acl) {
834 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
835 if (IS_ERR(bh)) {
836 ret = PTR_ERR(bh);
837 bh = NULL;
838 goto out;
839 }
840
841 ret = ext4_xattr_check_block(inode, bh);
842 if (ret)
843 goto out;
844
845 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
846 entry = EXT4_XATTR_NEXT(entry))
847 if (entry->e_value_inum)
848 ea_inode_refs++;
849 }
850 *usage = ea_inode_refs + 1;
851 ret = 0;
852out:
853 brelse(iloc.bh);
854 brelse(bh);
855 return ret;
856}
857
858static inline size_t round_up_cluster(struct inode *inode, size_t length)
859{
860 struct super_block *sb = inode->i_sb;
861 size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
862 inode->i_blkbits);
863 size_t mask = ~(cluster_size - 1);
864
865 return (length + cluster_size - 1) & mask;
866}
867
868static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
869{
870 int err;
871
872 err = dquot_alloc_inode(inode);
873 if (err)
874 return err;
875 err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
876 if (err)
877 dquot_free_inode(inode);
878 return err;
879}
880
881static void ext4_xattr_inode_free_quota(struct inode *parent,
882 struct inode *ea_inode,
883 size_t len)
884{
885 if (ea_inode &&
886 ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE))
887 return;
888 dquot_free_space_nodirty(parent, round_up_cluster(parent, len));
889 dquot_free_inode(parent);
890}
891
892int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
893 struct buffer_head *block_bh, size_t value_len,
894 bool is_create)
895{
896 int credits;
897 int blocks;
898
899 /*
900 * 1) Owner inode update
901 * 2) Ref count update on old xattr block
902 * 3) new xattr block
903 * 4) block bitmap update for new xattr block
904 * 5) group descriptor for new xattr block
905 * 6) block bitmap update for old xattr block
906 * 7) group descriptor for old block
907 *
908 * 6 & 7 can happen if we have two racing threads T_a and T_b
909 * which are each trying to set an xattr on inodes I_a and I_b
910 * which were both initially sharing an xattr block.
911 */
912 credits = 7;
913
914 /* Quota updates. */
915 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
916
917 /*
918 * In case of inline data, we may push out the data to a block,
919 * so we need to reserve credits for this eventuality
920 */
921 if (inode && ext4_has_inline_data(inode))
922 credits += ext4_writepage_trans_blocks(inode) + 1;
923
924 /* We are done if ea_inode feature is not enabled. */
925 if (!ext4_has_feature_ea_inode(sb))
926 return credits;
927
928 /* New ea_inode, inode map, block bitmap, group descriptor. */
929 credits += 4;
930
931 /* Data blocks. */
932 blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
933
934 /* Indirection block or one level of extent tree. */
935 blocks += 1;
936
937 /* Block bitmap and group descriptor updates for each block. */
938 credits += blocks * 2;
939
940 /* Blocks themselves. */
941 credits += blocks;
942
943 if (!is_create) {
944 /* Dereference ea_inode holding old xattr value.
945 * Old ea_inode, inode map, block bitmap, group descriptor.
946 */
947 credits += 4;
948
949 /* Data blocks for old ea_inode. */
950 blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
951
952 /* Indirection block or one level of extent tree for old
953 * ea_inode.
954 */
955 blocks += 1;
956
957 /* Block bitmap and group descriptor updates for each block. */
958 credits += blocks * 2;
959 }
960
961 /* We may need to clone the existing xattr block in which case we need
962 * to increment ref counts for existing ea_inodes referenced by it.
963 */
964 if (block_bh) {
965 struct ext4_xattr_entry *entry = BFIRST(block_bh);
966
967 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
968 if (entry->e_value_inum)
969 /* Ref count update on ea_inode. */
970 credits += 1;
971 }
972 return credits;
973}
974
975static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
976 int ref_change)
977{
978 struct mb_cache *ea_inode_cache = EA_INODE_CACHE(ea_inode);
979 struct ext4_iloc iloc;
980 s64 ref_count;
981 u32 hash;
982 int ret;
983
984 inode_lock(ea_inode);
985
986 ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
987 if (ret)
988 goto out;
989
990 ref_count = ext4_xattr_inode_get_ref(ea_inode);
991 ref_count += ref_change;
992 ext4_xattr_inode_set_ref(ea_inode, ref_count);
993
994 if (ref_change > 0) {
995 WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
996 ea_inode->i_ino, ref_count);
997
998 if (ref_count == 1) {
999 WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
1000 ea_inode->i_ino, ea_inode->i_nlink);
1001
1002 set_nlink(ea_inode, 1);
1003 ext4_orphan_del(handle, ea_inode);
1004
1005 if (ea_inode_cache) {
1006 hash = ext4_xattr_inode_get_hash(ea_inode);
1007 mb_cache_entry_create(ea_inode_cache,
1008 GFP_NOFS, hash,
1009 ea_inode->i_ino,
1010 true /* reusable */);
1011 }
1012 }
1013 } else {
1014 WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
1015 ea_inode->i_ino, ref_count);
1016
1017 if (ref_count == 0) {
1018 WARN_ONCE(ea_inode->i_nlink != 1,
1019 "EA inode %lu i_nlink=%u",
1020 ea_inode->i_ino, ea_inode->i_nlink);
1021
1022 clear_nlink(ea_inode);
1023 ext4_orphan_add(handle, ea_inode);
1024
1025 if (ea_inode_cache) {
1026 hash = ext4_xattr_inode_get_hash(ea_inode);
1027 mb_cache_entry_delete(ea_inode_cache, hash,
1028 ea_inode->i_ino);
1029 }
1030 }
1031 }
1032
1033 ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
1034 if (ret)
1035 ext4_warning_inode(ea_inode,
1036 "ext4_mark_iloc_dirty() failed ret=%d", ret);
1037out:
1038 inode_unlock(ea_inode);
1039 return ret;
1040}
1041
1042static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
1043{
1044 return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
1045}
1046
1047static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
1048{
1049 return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
1050}
1051
1052static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
1053 struct ext4_xattr_entry *first)
1054{
1055 struct inode *ea_inode;
1056 struct ext4_xattr_entry *entry;
1057 struct ext4_xattr_entry *failed_entry;
1058 unsigned int ea_ino;
1059 int err, saved_err;
1060
1061 for (entry = first; !IS_LAST_ENTRY(entry);
1062 entry = EXT4_XATTR_NEXT(entry)) {
1063 if (!entry->e_value_inum)
1064 continue;
1065 ea_ino = le32_to_cpu(entry->e_value_inum);
1066 err = ext4_xattr_inode_iget(parent, ea_ino,
1067 le32_to_cpu(entry->e_hash),
1068 &ea_inode);
1069 if (err)
1070 goto cleanup;
1071 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1072 if (err) {
1073 ext4_warning_inode(ea_inode, "inc ref error %d", err);
1074 iput(ea_inode);
1075 goto cleanup;
1076 }
1077 iput(ea_inode);
1078 }
1079 return 0;
1080
1081cleanup:
1082 saved_err = err;
1083 failed_entry = entry;
1084
1085 for (entry = first; entry != failed_entry;
1086 entry = EXT4_XATTR_NEXT(entry)) {
1087 if (!entry->e_value_inum)
1088 continue;
1089 ea_ino = le32_to_cpu(entry->e_value_inum);
1090 err = ext4_xattr_inode_iget(parent, ea_ino,
1091 le32_to_cpu(entry->e_hash),
1092 &ea_inode);
1093 if (err) {
1094 ext4_warning(parent->i_sb,
1095 "cleanup ea_ino %u iget error %d", ea_ino,
1096 err);
1097 continue;
1098 }
1099 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1100 if (err)
1101 ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
1102 err);
1103 iput(ea_inode);
1104 }
1105 return saved_err;
1106}
1107
1108static int ext4_xattr_restart_fn(handle_t *handle, struct inode *inode,
1109 struct buffer_head *bh, bool block_csum, bool dirty)
1110{
1111 int error;
1112
1113 if (bh && dirty) {
1114 if (block_csum)
1115 ext4_xattr_block_csum_set(inode, bh);
1116 error = ext4_handle_dirty_metadata(handle, NULL, bh);
1117 if (error) {
1118 ext4_warning(inode->i_sb, "Handle metadata (error %d)",
1119 error);
1120 return error;
1121 }
1122 }
1123 return 0;
1124}
1125
1126static void
1127ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
1128 struct buffer_head *bh,
1129 struct ext4_xattr_entry *first, bool block_csum,
1130 struct ext4_xattr_inode_array **ea_inode_array,
1131 int extra_credits, bool skip_quota)
1132{
1133 struct inode *ea_inode;
1134 struct ext4_xattr_entry *entry;
1135 bool dirty = false;
1136 unsigned int ea_ino;
1137 int err;
1138 int credits;
1139
1140 /* One credit for dec ref on ea_inode, one for orphan list addition, */
1141 credits = 2 + extra_credits;
1142
1143 for (entry = first; !IS_LAST_ENTRY(entry);
1144 entry = EXT4_XATTR_NEXT(entry)) {
1145 if (!entry->e_value_inum)
1146 continue;
1147 ea_ino = le32_to_cpu(entry->e_value_inum);
1148 err = ext4_xattr_inode_iget(parent, ea_ino,
1149 le32_to_cpu(entry->e_hash),
1150 &ea_inode);
1151 if (err)
1152 continue;
1153
1154 err = ext4_expand_inode_array(ea_inode_array, ea_inode);
1155 if (err) {
1156 ext4_warning_inode(ea_inode,
1157 "Expand inode array err=%d", err);
1158 iput(ea_inode);
1159 continue;
1160 }
1161
1162 err = ext4_journal_ensure_credits_fn(handle, credits, credits,
1163 ext4_free_metadata_revoke_credits(parent->i_sb, 1),
1164 ext4_xattr_restart_fn(handle, parent, bh, block_csum,
1165 dirty));
1166 if (err < 0) {
1167 ext4_warning_inode(ea_inode, "Ensure credits err=%d",
1168 err);
1169 continue;
1170 }
1171 if (err > 0) {
1172 err = ext4_journal_get_write_access(handle, bh);
1173 if (err) {
1174 ext4_warning_inode(ea_inode,
1175 "Re-get write access err=%d",
1176 err);
1177 continue;
1178 }
1179 }
1180
1181 err = ext4_xattr_inode_dec_ref(handle, ea_inode);
1182 if (err) {
1183 ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
1184 err);
1185 continue;
1186 }
1187
1188 if (!skip_quota)
1189 ext4_xattr_inode_free_quota(parent, ea_inode,
1190 le32_to_cpu(entry->e_value_size));
1191
1192 /*
1193 * Forget about ea_inode within the same transaction that
1194 * decrements the ref count. This avoids duplicate decrements in
1195 * case the rest of the work spills over to subsequent
1196 * transactions.
1197 */
1198 entry->e_value_inum = 0;
1199 entry->e_value_size = 0;
1200
1201 dirty = true;
1202 }
1203
1204 if (dirty) {
1205 /*
1206 * Note that we are deliberately skipping csum calculation for
1207 * the final update because we do not expect any journal
1208 * restarts until xattr block is freed.
1209 */
1210
1211 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1212 if (err)
1213 ext4_warning_inode(parent,
1214 "handle dirty metadata err=%d", err);
1215 }
1216}
1217
1218/*
1219 * Release the xattr block BH: If the reference count is > 1, decrement it;
1220 * otherwise free the block.
1221 */
1222static void
1223ext4_xattr_release_block(handle_t *handle, struct inode *inode,
1224 struct buffer_head *bh,
1225 struct ext4_xattr_inode_array **ea_inode_array,
1226 int extra_credits)
1227{
1228 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1229 u32 hash, ref;
1230 int error = 0;
1231
1232 BUFFER_TRACE(bh, "get_write_access");
1233 error = ext4_journal_get_write_access(handle, bh);
1234 if (error)
1235 goto out;
1236
1237 lock_buffer(bh);
1238 hash = le32_to_cpu(BHDR(bh)->h_hash);
1239 ref = le32_to_cpu(BHDR(bh)->h_refcount);
1240 if (ref == 1) {
1241 ea_bdebug(bh, "refcount now=0; freeing");
1242 /*
1243 * This must happen under buffer lock for
1244 * ext4_xattr_block_set() to reliably detect freed block
1245 */
1246 if (ea_block_cache)
1247 mb_cache_entry_delete(ea_block_cache, hash,
1248 bh->b_blocknr);
1249 get_bh(bh);
1250 unlock_buffer(bh);
1251
1252 if (ext4_has_feature_ea_inode(inode->i_sb))
1253 ext4_xattr_inode_dec_ref_all(handle, inode, bh,
1254 BFIRST(bh),
1255 true /* block_csum */,
1256 ea_inode_array,
1257 extra_credits,
1258 true /* skip_quota */);
1259 ext4_free_blocks(handle, inode, bh, 0, 1,
1260 EXT4_FREE_BLOCKS_METADATA |
1261 EXT4_FREE_BLOCKS_FORGET);
1262 } else {
1263 ref--;
1264 BHDR(bh)->h_refcount = cpu_to_le32(ref);
1265 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
1266 struct mb_cache_entry *ce;
1267
1268 if (ea_block_cache) {
1269 ce = mb_cache_entry_get(ea_block_cache, hash,
1270 bh->b_blocknr);
1271 if (ce) {
1272 ce->e_reusable = 1;
1273 mb_cache_entry_put(ea_block_cache, ce);
1274 }
1275 }
1276 }
1277
1278 ext4_xattr_block_csum_set(inode, bh);
1279 /*
1280 * Beware of this ugliness: Releasing of xattr block references
1281 * from different inodes can race and so we have to protect
1282 * from a race where someone else frees the block (and releases
1283 * its journal_head) before we are done dirtying the buffer. In
1284 * nojournal mode this race is harmless and we actually cannot
1285 * call ext4_handle_dirty_metadata() with locked buffer as
1286 * that function can call sync_dirty_buffer() so for that case
1287 * we handle the dirtying after unlocking the buffer.
1288 */
1289 if (ext4_handle_valid(handle))
1290 error = ext4_handle_dirty_metadata(handle, inode, bh);
1291 unlock_buffer(bh);
1292 if (!ext4_handle_valid(handle))
1293 error = ext4_handle_dirty_metadata(handle, inode, bh);
1294 if (IS_SYNC(inode))
1295 ext4_handle_sync(handle);
1296 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
1297 ea_bdebug(bh, "refcount now=%d; releasing",
1298 le32_to_cpu(BHDR(bh)->h_refcount));
1299 }
1300out:
1301 ext4_std_error(inode->i_sb, error);
1302 return;
1303}
1304
1305/*
1306 * Find the available free space for EAs. This also returns the total number of
1307 * bytes used by EA entries.
1308 */
1309static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last,
1310 size_t *min_offs, void *base, int *total)
1311{
1312 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
1313 if (!last->e_value_inum && last->e_value_size) {
1314 size_t offs = le16_to_cpu(last->e_value_offs);
1315 if (offs < *min_offs)
1316 *min_offs = offs;
1317 }
1318 if (total)
1319 *total += EXT4_XATTR_LEN(last->e_name_len);
1320 }
1321 return (*min_offs - ((void *)last - base) - sizeof(__u32));
1322}
1323
1324/*
1325 * Write the value of the EA in an inode.
1326 */
1327static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
1328 const void *buf, int bufsize)
1329{
1330 struct buffer_head *bh = NULL;
1331 unsigned long block = 0;
1332 int blocksize = ea_inode->i_sb->s_blocksize;
1333 int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
1334 int csize, wsize = 0;
1335 int ret = 0, ret2 = 0;
1336 int retries = 0;
1337
1338retry:
1339 while (ret >= 0 && ret < max_blocks) {
1340 struct ext4_map_blocks map;
1341 map.m_lblk = block += ret;
1342 map.m_len = max_blocks -= ret;
1343
1344 ret = ext4_map_blocks(handle, ea_inode, &map,
1345 EXT4_GET_BLOCKS_CREATE);
1346 if (ret <= 0) {
1347 ext4_mark_inode_dirty(handle, ea_inode);
1348 if (ret == -ENOSPC &&
1349 ext4_should_retry_alloc(ea_inode->i_sb, &retries)) {
1350 ret = 0;
1351 goto retry;
1352 }
1353 break;
1354 }
1355 }
1356
1357 if (ret < 0)
1358 return ret;
1359
1360 block = 0;
1361 while (wsize < bufsize) {
1362 brelse(bh);
1363 csize = (bufsize - wsize) > blocksize ? blocksize :
1364 bufsize - wsize;
1365 bh = ext4_getblk(handle, ea_inode, block, 0);
1366 if (IS_ERR(bh))
1367 return PTR_ERR(bh);
1368 if (!bh) {
1369 WARN_ON_ONCE(1);
1370 EXT4_ERROR_INODE(ea_inode,
1371 "ext4_getblk() return bh = NULL");
1372 return -EFSCORRUPTED;
1373 }
1374 ret = ext4_journal_get_write_access(handle, bh);
1375 if (ret)
1376 goto out;
1377
1378 memcpy(bh->b_data, buf, csize);
1379 set_buffer_uptodate(bh);
1380 ext4_handle_dirty_metadata(handle, ea_inode, bh);
1381
1382 buf += csize;
1383 wsize += csize;
1384 block += 1;
1385 }
1386
1387 inode_lock(ea_inode);
1388 i_size_write(ea_inode, wsize);
1389 ext4_update_i_disksize(ea_inode, wsize);
1390 inode_unlock(ea_inode);
1391
1392 ret2 = ext4_mark_inode_dirty(handle, ea_inode);
1393 if (unlikely(ret2 && !ret))
1394 ret = ret2;
1395
1396out:
1397 brelse(bh);
1398
1399 return ret;
1400}
1401
1402/*
1403 * Create an inode to store the value of a large EA.
1404 */
1405static struct inode *ext4_xattr_inode_create(handle_t *handle,
1406 struct inode *inode, u32 hash)
1407{
1408 struct inode *ea_inode = NULL;
1409 uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
1410 int err;
1411
1412 /*
1413 * Let the next inode be the goal, so we try and allocate the EA inode
1414 * in the same group, or nearby one.
1415 */
1416 ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
1417 S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
1418 EXT4_EA_INODE_FL);
1419 if (!IS_ERR(ea_inode)) {
1420 ea_inode->i_op = &ext4_file_inode_operations;
1421 ea_inode->i_fop = &ext4_file_operations;
1422 ext4_set_aops(ea_inode);
1423 ext4_xattr_inode_set_class(ea_inode);
1424 unlock_new_inode(ea_inode);
1425 ext4_xattr_inode_set_ref(ea_inode, 1);
1426 ext4_xattr_inode_set_hash(ea_inode, hash);
1427 err = ext4_mark_inode_dirty(handle, ea_inode);
1428 if (!err)
1429 err = ext4_inode_attach_jinode(ea_inode);
1430 if (err) {
1431 iput(ea_inode);
1432 return ERR_PTR(err);
1433 }
1434
1435 /*
1436 * Xattr inodes are shared therefore quota charging is performed
1437 * at a higher level.
1438 */
1439 dquot_free_inode(ea_inode);
1440 dquot_drop(ea_inode);
1441 inode_lock(ea_inode);
1442 ea_inode->i_flags |= S_NOQUOTA;
1443 inode_unlock(ea_inode);
1444 }
1445
1446 return ea_inode;
1447}
1448
1449static struct inode *
1450ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
1451 size_t value_len, u32 hash)
1452{
1453 struct inode *ea_inode;
1454 struct mb_cache_entry *ce;
1455 struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
1456 void *ea_data;
1457
1458 if (!ea_inode_cache)
1459 return NULL;
1460
1461 ce = mb_cache_entry_find_first(ea_inode_cache, hash);
1462 if (!ce)
1463 return NULL;
1464
1465 WARN_ON_ONCE(ext4_handle_valid(journal_current_handle()) &&
1466 !(current->flags & PF_MEMALLOC_NOFS));
1467
1468 ea_data = kvmalloc(value_len, GFP_KERNEL);
1469 if (!ea_data) {
1470 mb_cache_entry_put(ea_inode_cache, ce);
1471 return NULL;
1472 }
1473
1474 while (ce) {
1475 ea_inode = ext4_iget(inode->i_sb, ce->e_value,
1476 EXT4_IGET_NORMAL);
1477 if (!IS_ERR(ea_inode) &&
1478 !is_bad_inode(ea_inode) &&
1479 (EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) &&
1480 i_size_read(ea_inode) == value_len &&
1481 !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
1482 !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
1483 value_len) &&
1484 !memcmp(value, ea_data, value_len)) {
1485 mb_cache_entry_touch(ea_inode_cache, ce);
1486 mb_cache_entry_put(ea_inode_cache, ce);
1487 kvfree(ea_data);
1488 return ea_inode;
1489 }
1490
1491 if (!IS_ERR(ea_inode))
1492 iput(ea_inode);
1493 ce = mb_cache_entry_find_next(ea_inode_cache, ce);
1494 }
1495 kvfree(ea_data);
1496 return NULL;
1497}
1498
1499/*
1500 * Add value of the EA in an inode.
1501 */
1502static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
1503 const void *value, size_t value_len,
1504 struct inode **ret_inode)
1505{
1506 struct inode *ea_inode;
1507 u32 hash;
1508 int err;
1509
1510 hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
1511 ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
1512 if (ea_inode) {
1513 err = ext4_xattr_inode_inc_ref(handle, ea_inode);
1514 if (err) {
1515 iput(ea_inode);
1516 return err;
1517 }
1518
1519 *ret_inode = ea_inode;
1520 return 0;
1521 }
1522
1523 /* Create an inode for the EA value */
1524 ea_inode = ext4_xattr_inode_create(handle, inode, hash);
1525 if (IS_ERR(ea_inode))
1526 return PTR_ERR(ea_inode);
1527
1528 err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
1529 if (err) {
1530 ext4_xattr_inode_dec_ref(handle, ea_inode);
1531 iput(ea_inode);
1532 return err;
1533 }
1534
1535 if (EA_INODE_CACHE(inode))
1536 mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
1537 ea_inode->i_ino, true /* reusable */);
1538
1539 *ret_inode = ea_inode;
1540 return 0;
1541}
1542
1543/*
1544 * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode
1545 * feature is enabled.
1546 */
1547#define EXT4_XATTR_BLOCK_RESERVE(inode) min(i_blocksize(inode)/8, 1024U)
1548
1549static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
1550 struct ext4_xattr_search *s,
1551 handle_t *handle, struct inode *inode,
1552 bool is_block)
1553{
1554 struct ext4_xattr_entry *last, *next;
1555 struct ext4_xattr_entry *here = s->here;
1556 size_t min_offs = s->end - s->base, name_len = strlen(i->name);
1557 int in_inode = i->in_inode;
1558 struct inode *old_ea_inode = NULL;
1559 struct inode *new_ea_inode = NULL;
1560 size_t old_size, new_size;
1561 int ret;
1562
1563 /* Space used by old and new values. */
1564 old_size = (!s->not_found && !here->e_value_inum) ?
1565 EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
1566 new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
1567
1568 /*
1569 * Optimization for the simple case when old and new values have the
1570 * same padded sizes. Not applicable if external inodes are involved.
1571 */
1572 if (new_size && new_size == old_size) {
1573 size_t offs = le16_to_cpu(here->e_value_offs);
1574 void *val = s->base + offs;
1575
1576 here->e_value_size = cpu_to_le32(i->value_len);
1577 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1578 memset(val, 0, new_size);
1579 } else {
1580 memcpy(val, i->value, i->value_len);
1581 /* Clear padding bytes. */
1582 memset(val + i->value_len, 0, new_size - i->value_len);
1583 }
1584 goto update_hash;
1585 }
1586
1587 /* Compute min_offs and last. */
1588 last = s->first;
1589 for (; !IS_LAST_ENTRY(last); last = next) {
1590 next = EXT4_XATTR_NEXT(last);
1591 if ((void *)next >= s->end) {
1592 EXT4_ERROR_INODE(inode, "corrupted xattr entries");
1593 ret = -EFSCORRUPTED;
1594 goto out;
1595 }
1596 if (!last->e_value_inum && last->e_value_size) {
1597 size_t offs = le16_to_cpu(last->e_value_offs);
1598 if (offs < min_offs)
1599 min_offs = offs;
1600 }
1601 }
1602
1603 /* Check whether we have enough space. */
1604 if (i->value) {
1605 size_t free;
1606
1607 free = min_offs - ((void *)last - s->base) - sizeof(__u32);
1608 if (!s->not_found)
1609 free += EXT4_XATTR_LEN(name_len) + old_size;
1610
1611 if (free < EXT4_XATTR_LEN(name_len) + new_size) {
1612 ret = -ENOSPC;
1613 goto out;
1614 }
1615
1616 /*
1617 * If storing the value in an external inode is an option,
1618 * reserve space for xattr entries/names in the external
1619 * attribute block so that a long value does not occupy the
1620 * whole space and prevent further entries being added.
1621 */
1622 if (ext4_has_feature_ea_inode(inode->i_sb) &&
1623 new_size && is_block &&
1624 (min_offs + old_size - new_size) <
1625 EXT4_XATTR_BLOCK_RESERVE(inode)) {
1626 ret = -ENOSPC;
1627 goto out;
1628 }
1629 }
1630
1631 /*
1632 * Getting access to old and new ea inodes is subject to failures.
1633 * Finish that work before doing any modifications to the xattr data.
1634 */
1635 if (!s->not_found && here->e_value_inum) {
1636 ret = ext4_xattr_inode_iget(inode,
1637 le32_to_cpu(here->e_value_inum),
1638 le32_to_cpu(here->e_hash),
1639 &old_ea_inode);
1640 if (ret) {
1641 old_ea_inode = NULL;
1642 goto out;
1643 }
1644 }
1645 if (i->value && in_inode) {
1646 WARN_ON_ONCE(!i->value_len);
1647
1648 ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
1649 if (ret)
1650 goto out;
1651
1652 ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
1653 i->value_len,
1654 &new_ea_inode);
1655 if (ret) {
1656 new_ea_inode = NULL;
1657 ext4_xattr_inode_free_quota(inode, NULL, i->value_len);
1658 goto out;
1659 }
1660 }
1661
1662 if (old_ea_inode) {
1663 /* We are ready to release ref count on the old_ea_inode. */
1664 ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
1665 if (ret) {
1666 /* Release newly required ref count on new_ea_inode. */
1667 if (new_ea_inode) {
1668 int err;
1669
1670 err = ext4_xattr_inode_dec_ref(handle,
1671 new_ea_inode);
1672 if (err)
1673 ext4_warning_inode(new_ea_inode,
1674 "dec ref new_ea_inode err=%d",
1675 err);
1676 ext4_xattr_inode_free_quota(inode, new_ea_inode,
1677 i->value_len);
1678 }
1679 goto out;
1680 }
1681
1682 ext4_xattr_inode_free_quota(inode, old_ea_inode,
1683 le32_to_cpu(here->e_value_size));
1684 }
1685
1686 /* No failures allowed past this point. */
1687
1688 if (!s->not_found && here->e_value_size && !here->e_value_inum) {
1689 /* Remove the old value. */
1690 void *first_val = s->base + min_offs;
1691 size_t offs = le16_to_cpu(here->e_value_offs);
1692 void *val = s->base + offs;
1693
1694 memmove(first_val + old_size, first_val, val - first_val);
1695 memset(first_val, 0, old_size);
1696 min_offs += old_size;
1697
1698 /* Adjust all value offsets. */
1699 last = s->first;
1700 while (!IS_LAST_ENTRY(last)) {
1701 size_t o = le16_to_cpu(last->e_value_offs);
1702
1703 if (!last->e_value_inum &&
1704 last->e_value_size && o < offs)
1705 last->e_value_offs = cpu_to_le16(o + old_size);
1706 last = EXT4_XATTR_NEXT(last);
1707 }
1708 }
1709
1710 if (!i->value) {
1711 /* Remove old name. */
1712 size_t size = EXT4_XATTR_LEN(name_len);
1713
1714 last = ENTRY((void *)last - size);
1715 memmove(here, (void *)here + size,
1716 (void *)last - (void *)here + sizeof(__u32));
1717 memset(last, 0, size);
1718 } else if (s->not_found) {
1719 /* Insert new name. */
1720 size_t size = EXT4_XATTR_LEN(name_len);
1721 size_t rest = (void *)last - (void *)here + sizeof(__u32);
1722
1723 memmove((void *)here + size, here, rest);
1724 memset(here, 0, size);
1725 here->e_name_index = i->name_index;
1726 here->e_name_len = name_len;
1727 memcpy(here->e_name, i->name, name_len);
1728 } else {
1729 /* This is an update, reset value info. */
1730 here->e_value_inum = 0;
1731 here->e_value_offs = 0;
1732 here->e_value_size = 0;
1733 }
1734
1735 if (i->value) {
1736 /* Insert new value. */
1737 if (in_inode) {
1738 here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
1739 } else if (i->value_len) {
1740 void *val = s->base + min_offs - new_size;
1741
1742 here->e_value_offs = cpu_to_le16(min_offs - new_size);
1743 if (i->value == EXT4_ZERO_XATTR_VALUE) {
1744 memset(val, 0, new_size);
1745 } else {
1746 memcpy(val, i->value, i->value_len);
1747 /* Clear padding bytes. */
1748 memset(val + i->value_len, 0,
1749 new_size - i->value_len);
1750 }
1751 }
1752 here->e_value_size = cpu_to_le32(i->value_len);
1753 }
1754
1755update_hash:
1756 if (i->value) {
1757 __le32 hash = 0;
1758
1759 /* Entry hash calculation. */
1760 if (in_inode) {
1761 __le32 crc32c_hash;
1762
1763 /*
1764 * Feed crc32c hash instead of the raw value for entry
1765 * hash calculation. This is to avoid walking
1766 * potentially long value buffer again.
1767 */
1768 crc32c_hash = cpu_to_le32(
1769 ext4_xattr_inode_get_hash(new_ea_inode));
1770 hash = ext4_xattr_hash_entry(here->e_name,
1771 here->e_name_len,
1772 &crc32c_hash, 1);
1773 } else if (is_block) {
1774 __le32 *value = s->base + le16_to_cpu(
1775 here->e_value_offs);
1776
1777 hash = ext4_xattr_hash_entry(here->e_name,
1778 here->e_name_len, value,
1779 new_size >> 2);
1780 }
1781 here->e_hash = hash;
1782 }
1783
1784 if (is_block)
1785 ext4_xattr_rehash((struct ext4_xattr_header *)s->base);
1786
1787 ret = 0;
1788out:
1789 iput(old_ea_inode);
1790 iput(new_ea_inode);
1791 return ret;
1792}
1793
1794struct ext4_xattr_block_find {
1795 struct ext4_xattr_search s;
1796 struct buffer_head *bh;
1797};
1798
1799static int
1800ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
1801 struct ext4_xattr_block_find *bs)
1802{
1803 struct super_block *sb = inode->i_sb;
1804 int error;
1805
1806 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
1807 i->name_index, i->name, i->value, (long)i->value_len);
1808
1809 if (EXT4_I(inode)->i_file_acl) {
1810 /* The inode already has an extended attribute block. */
1811 bs->bh = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
1812 if (IS_ERR(bs->bh)) {
1813 error = PTR_ERR(bs->bh);
1814 bs->bh = NULL;
1815 return error;
1816 }
1817 ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
1818 atomic_read(&(bs->bh->b_count)),
1819 le32_to_cpu(BHDR(bs->bh)->h_refcount));
1820 error = ext4_xattr_check_block(inode, bs->bh);
1821 if (error)
1822 return error;
1823 /* Find the named attribute. */
1824 bs->s.base = BHDR(bs->bh);
1825 bs->s.first = BFIRST(bs->bh);
1826 bs->s.end = bs->bh->b_data + bs->bh->b_size;
1827 bs->s.here = bs->s.first;
1828 error = xattr_find_entry(inode, &bs->s.here, bs->s.end,
1829 i->name_index, i->name, 1);
1830 if (error && error != -ENODATA)
1831 return error;
1832 bs->s.not_found = error;
1833 }
1834 return 0;
1835}
1836
1837static int
1838ext4_xattr_block_set(handle_t *handle, struct inode *inode,
1839 struct ext4_xattr_info *i,
1840 struct ext4_xattr_block_find *bs)
1841{
1842 struct super_block *sb = inode->i_sb;
1843 struct buffer_head *new_bh = NULL;
1844 struct ext4_xattr_search s_copy = bs->s;
1845 struct ext4_xattr_search *s = &s_copy;
1846 struct mb_cache_entry *ce = NULL;
1847 int error = 0;
1848 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
1849 struct inode *ea_inode = NULL, *tmp_inode;
1850 size_t old_ea_inode_quota = 0;
1851 unsigned int ea_ino;
1852
1853
1854#define header(x) ((struct ext4_xattr_header *)(x))
1855
1856 if (s->base) {
1857 BUFFER_TRACE(bs->bh, "get_write_access");
1858 error = ext4_journal_get_write_access(handle, bs->bh);
1859 if (error)
1860 goto cleanup;
1861 lock_buffer(bs->bh);
1862
1863 if (header(s->base)->h_refcount == cpu_to_le32(1)) {
1864 __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash);
1865
1866 /*
1867 * This must happen under buffer lock for
1868 * ext4_xattr_block_set() to reliably detect modified
1869 * block
1870 */
1871 if (ea_block_cache)
1872 mb_cache_entry_delete(ea_block_cache, hash,
1873 bs->bh->b_blocknr);
1874 ea_bdebug(bs->bh, "modifying in-place");
1875 error = ext4_xattr_set_entry(i, s, handle, inode,
1876 true /* is_block */);
1877 ext4_xattr_block_csum_set(inode, bs->bh);
1878 unlock_buffer(bs->bh);
1879 if (error == -EFSCORRUPTED)
1880 goto bad_block;
1881 if (!error)
1882 error = ext4_handle_dirty_metadata(handle,
1883 inode,
1884 bs->bh);
1885 if (error)
1886 goto cleanup;
1887 goto inserted;
1888 } else {
1889 int offset = (char *)s->here - bs->bh->b_data;
1890
1891 unlock_buffer(bs->bh);
1892 ea_bdebug(bs->bh, "cloning");
1893 s->base = kmalloc(bs->bh->b_size, GFP_NOFS);
1894 error = -ENOMEM;
1895 if (s->base == NULL)
1896 goto cleanup;
1897 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
1898 s->first = ENTRY(header(s->base)+1);
1899 header(s->base)->h_refcount = cpu_to_le32(1);
1900 s->here = ENTRY(s->base + offset);
1901 s->end = s->base + bs->bh->b_size;
1902
1903 /*
1904 * If existing entry points to an xattr inode, we need
1905 * to prevent ext4_xattr_set_entry() from decrementing
1906 * ref count on it because the reference belongs to the
1907 * original block. In this case, make the entry look
1908 * like it has an empty value.
1909 */
1910 if (!s->not_found && s->here->e_value_inum) {
1911 ea_ino = le32_to_cpu(s->here->e_value_inum);
1912 error = ext4_xattr_inode_iget(inode, ea_ino,
1913 le32_to_cpu(s->here->e_hash),
1914 &tmp_inode);
1915 if (error)
1916 goto cleanup;
1917
1918 if (!ext4_test_inode_state(tmp_inode,
1919 EXT4_STATE_LUSTRE_EA_INODE)) {
1920 /*
1921 * Defer quota free call for previous
1922 * inode until success is guaranteed.
1923 */
1924 old_ea_inode_quota = le32_to_cpu(
1925 s->here->e_value_size);
1926 }
1927 iput(tmp_inode);
1928
1929 s->here->e_value_inum = 0;
1930 s->here->e_value_size = 0;
1931 }
1932 }
1933 } else {
1934 /* Allocate a buffer where we construct the new block. */
1935 s->base = kzalloc(sb->s_blocksize, GFP_NOFS);
1936 error = -ENOMEM;
1937 if (s->base == NULL)
1938 goto cleanup;
1939 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
1940 header(s->base)->h_blocks = cpu_to_le32(1);
1941 header(s->base)->h_refcount = cpu_to_le32(1);
1942 s->first = ENTRY(header(s->base)+1);
1943 s->here = ENTRY(header(s->base)+1);
1944 s->end = s->base + sb->s_blocksize;
1945 }
1946
1947 error = ext4_xattr_set_entry(i, s, handle, inode, true /* is_block */);
1948 if (error == -EFSCORRUPTED)
1949 goto bad_block;
1950 if (error)
1951 goto cleanup;
1952
1953 if (i->value && s->here->e_value_inum) {
1954 /*
1955 * A ref count on ea_inode has been taken as part of the call to
1956 * ext4_xattr_set_entry() above. We would like to drop this
1957 * extra ref but we have to wait until the xattr block is
1958 * initialized and has its own ref count on the ea_inode.
1959 */
1960 ea_ino = le32_to_cpu(s->here->e_value_inum);
1961 error = ext4_xattr_inode_iget(inode, ea_ino,
1962 le32_to_cpu(s->here->e_hash),
1963 &ea_inode);
1964 if (error) {
1965 ea_inode = NULL;
1966 goto cleanup;
1967 }
1968 }
1969
1970inserted:
1971 if (!IS_LAST_ENTRY(s->first)) {
1972 new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
1973 &ce);
1974 if (new_bh) {
1975 /* We found an identical block in the cache. */
1976 if (new_bh == bs->bh)
1977 ea_bdebug(new_bh, "keeping");
1978 else {
1979 u32 ref;
1980
1981 WARN_ON_ONCE(dquot_initialize_needed(inode));
1982
1983 /* The old block is released after updating
1984 the inode. */
1985 error = dquot_alloc_block(inode,
1986 EXT4_C2B(EXT4_SB(sb), 1));
1987 if (error)
1988 goto cleanup;
1989 BUFFER_TRACE(new_bh, "get_write_access");
1990 error = ext4_journal_get_write_access(handle,
1991 new_bh);
1992 if (error)
1993 goto cleanup_dquot;
1994 lock_buffer(new_bh);
1995 /*
1996 * We have to be careful about races with
1997 * freeing, rehashing or adding references to
1998 * xattr block. Once we hold buffer lock xattr
1999 * block's state is stable so we can check
2000 * whether the block got freed / rehashed or
2001 * not. Since we unhash mbcache entry under
2002 * buffer lock when freeing / rehashing xattr
2003 * block, checking whether entry is still
2004 * hashed is reliable. Same rules hold for
2005 * e_reusable handling.
2006 */
2007 if (hlist_bl_unhashed(&ce->e_hash_list) ||
2008 !ce->e_reusable) {
2009 /*
2010 * Undo everything and check mbcache
2011 * again.
2012 */
2013 unlock_buffer(new_bh);
2014 dquot_free_block(inode,
2015 EXT4_C2B(EXT4_SB(sb),
2016 1));
2017 brelse(new_bh);
2018 mb_cache_entry_put(ea_block_cache, ce);
2019 ce = NULL;
2020 new_bh = NULL;
2021 goto inserted;
2022 }
2023 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1;
2024 BHDR(new_bh)->h_refcount = cpu_to_le32(ref);
2025 if (ref >= EXT4_XATTR_REFCOUNT_MAX)
2026 ce->e_reusable = 0;
2027 ea_bdebug(new_bh, "reusing; refcount now=%d",
2028 ref);
2029 ext4_xattr_block_csum_set(inode, new_bh);
2030 unlock_buffer(new_bh);
2031 error = ext4_handle_dirty_metadata(handle,
2032 inode,
2033 new_bh);
2034 if (error)
2035 goto cleanup_dquot;
2036 }
2037 mb_cache_entry_touch(ea_block_cache, ce);
2038 mb_cache_entry_put(ea_block_cache, ce);
2039 ce = NULL;
2040 } else if (bs->bh && s->base == bs->bh->b_data) {
2041 /* We were modifying this block in-place. */
2042 ea_bdebug(bs->bh, "keeping this block");
2043 ext4_xattr_block_cache_insert(ea_block_cache, bs->bh);
2044 new_bh = bs->bh;
2045 get_bh(new_bh);
2046 } else {
2047 /* We need to allocate a new block */
2048 ext4_fsblk_t goal, block;
2049
2050 WARN_ON_ONCE(dquot_initialize_needed(inode));
2051
2052 goal = ext4_group_first_block_no(sb,
2053 EXT4_I(inode)->i_block_group);
2054
2055 /* non-extent files can't have physical blocks past 2^32 */
2056 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2057 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
2058
2059 block = ext4_new_meta_blocks(handle, inode, goal, 0,
2060 NULL, &error);
2061 if (error)
2062 goto cleanup;
2063
2064 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
2065 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS);
2066
2067 ea_idebug(inode, "creating block %llu",
2068 (unsigned long long)block);
2069
2070 new_bh = sb_getblk(sb, block);
2071 if (unlikely(!new_bh)) {
2072 error = -ENOMEM;
2073getblk_failed:
2074 ext4_free_blocks(handle, inode, NULL, block, 1,
2075 EXT4_FREE_BLOCKS_METADATA);
2076 goto cleanup;
2077 }
2078 error = ext4_xattr_inode_inc_ref_all(handle, inode,
2079 ENTRY(header(s->base)+1));
2080 if (error)
2081 goto getblk_failed;
2082 if (ea_inode) {
2083 /* Drop the extra ref on ea_inode. */
2084 error = ext4_xattr_inode_dec_ref(handle,
2085 ea_inode);
2086 if (error)
2087 ext4_warning_inode(ea_inode,
2088 "dec ref error=%d",
2089 error);
2090 iput(ea_inode);
2091 ea_inode = NULL;
2092 }
2093
2094 lock_buffer(new_bh);
2095 error = ext4_journal_get_create_access(handle, new_bh);
2096 if (error) {
2097 unlock_buffer(new_bh);
2098 error = -EIO;
2099 goto getblk_failed;
2100 }
2101 memcpy(new_bh->b_data, s->base, new_bh->b_size);
2102 ext4_xattr_block_csum_set(inode, new_bh);
2103 set_buffer_uptodate(new_bh);
2104 unlock_buffer(new_bh);
2105 ext4_xattr_block_cache_insert(ea_block_cache, new_bh);
2106 error = ext4_handle_dirty_metadata(handle, inode,
2107 new_bh);
2108 if (error)
2109 goto cleanup;
2110 }
2111 }
2112
2113 if (old_ea_inode_quota)
2114 ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota);
2115
2116 /* Update the inode. */
2117 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
2118
2119 /* Drop the previous xattr block. */
2120 if (bs->bh && bs->bh != new_bh) {
2121 struct ext4_xattr_inode_array *ea_inode_array = NULL;
2122
2123 ext4_xattr_release_block(handle, inode, bs->bh,
2124 &ea_inode_array,
2125 0 /* extra_credits */);
2126 ext4_xattr_inode_array_free(ea_inode_array);
2127 }
2128 error = 0;
2129
2130cleanup:
2131 if (ea_inode) {
2132 int error2;
2133
2134 error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
2135 if (error2)
2136 ext4_warning_inode(ea_inode, "dec ref error=%d",
2137 error2);
2138
2139 /* If there was an error, revert the quota charge. */
2140 if (error)
2141 ext4_xattr_inode_free_quota(inode, ea_inode,
2142 i_size_read(ea_inode));
2143 iput(ea_inode);
2144 }
2145 if (ce)
2146 mb_cache_entry_put(ea_block_cache, ce);
2147 brelse(new_bh);
2148 if (!(bs->bh && s->base == bs->bh->b_data))
2149 kfree(s->base);
2150
2151 return error;
2152
2153cleanup_dquot:
2154 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1));
2155 goto cleanup;
2156
2157bad_block:
2158 EXT4_ERROR_INODE(inode, "bad block %llu",
2159 EXT4_I(inode)->i_file_acl);
2160 goto cleanup;
2161
2162#undef header
2163}
2164
2165int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
2166 struct ext4_xattr_ibody_find *is)
2167{
2168 struct ext4_xattr_ibody_header *header;
2169 struct ext4_inode *raw_inode;
2170 int error;
2171
2172 if (EXT4_I(inode)->i_extra_isize == 0)
2173 return 0;
2174 raw_inode = ext4_raw_inode(&is->iloc);
2175 header = IHDR(inode, raw_inode);
2176 is->s.base = is->s.first = IFIRST(header);
2177 is->s.here = is->s.first;
2178 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2179 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2180 error = xattr_check_inode(inode, header, is->s.end);
2181 if (error)
2182 return error;
2183 /* Find the named attribute. */
2184 error = xattr_find_entry(inode, &is->s.here, is->s.end,
2185 i->name_index, i->name, 0);
2186 if (error && error != -ENODATA)
2187 return error;
2188 is->s.not_found = error;
2189 }
2190 return 0;
2191}
2192
2193int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
2194 struct ext4_xattr_info *i,
2195 struct ext4_xattr_ibody_find *is)
2196{
2197 struct ext4_xattr_ibody_header *header;
2198 struct ext4_xattr_search *s = &is->s;
2199 int error;
2200
2201 if (EXT4_I(inode)->i_extra_isize == 0)
2202 return -ENOSPC;
2203 error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */);
2204 if (error)
2205 return error;
2206 header = IHDR(inode, ext4_raw_inode(&is->iloc));
2207 if (!IS_LAST_ENTRY(s->first)) {
2208 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
2209 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
2210 } else {
2211 header->h_magic = cpu_to_le32(0);
2212 ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
2213 }
2214 return 0;
2215}
2216
2217static int ext4_xattr_value_same(struct ext4_xattr_search *s,
2218 struct ext4_xattr_info *i)
2219{
2220 void *value;
2221
2222 /* When e_value_inum is set the value is stored externally. */
2223 if (s->here->e_value_inum)
2224 return 0;
2225 if (le32_to_cpu(s->here->e_value_size) != i->value_len)
2226 return 0;
2227 value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
2228 return !memcmp(value, i->value, i->value_len);
2229}
2230
2231static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
2232{
2233 struct buffer_head *bh;
2234 int error;
2235
2236 if (!EXT4_I(inode)->i_file_acl)
2237 return NULL;
2238 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2239 if (IS_ERR(bh))
2240 return bh;
2241 error = ext4_xattr_check_block(inode, bh);
2242 if (error) {
2243 brelse(bh);
2244 return ERR_PTR(error);
2245 }
2246 return bh;
2247}
2248
2249/*
2250 * ext4_xattr_set_handle()
2251 *
2252 * Create, replace or remove an extended attribute for this inode. Value
2253 * is NULL to remove an existing extended attribute, and non-NULL to
2254 * either replace an existing extended attribute, or create a new extended
2255 * attribute. The flags XATTR_REPLACE and XATTR_CREATE
2256 * specify that an extended attribute must exist and must not exist
2257 * previous to the call, respectively.
2258 *
2259 * Returns 0, or a negative error number on failure.
2260 */
2261int
2262ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
2263 const char *name, const void *value, size_t value_len,
2264 int flags)
2265{
2266 struct ext4_xattr_info i = {
2267 .name_index = name_index,
2268 .name = name,
2269 .value = value,
2270 .value_len = value_len,
2271 .in_inode = 0,
2272 };
2273 struct ext4_xattr_ibody_find is = {
2274 .s = { .not_found = -ENODATA, },
2275 };
2276 struct ext4_xattr_block_find bs = {
2277 .s = { .not_found = -ENODATA, },
2278 };
2279 int no_expand;
2280 int error;
2281
2282 if (!name)
2283 return -EINVAL;
2284 if (strlen(name) > 255)
2285 return -ERANGE;
2286
2287 ext4_write_lock_xattr(inode, &no_expand);
2288
2289 /* Check journal credits under write lock. */
2290 if (ext4_handle_valid(handle)) {
2291 struct buffer_head *bh;
2292 int credits;
2293
2294 bh = ext4_xattr_get_block(inode);
2295 if (IS_ERR(bh)) {
2296 error = PTR_ERR(bh);
2297 goto cleanup;
2298 }
2299
2300 credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2301 value_len,
2302 flags & XATTR_CREATE);
2303 brelse(bh);
2304
2305 if (jbd2_handle_buffer_credits(handle) < credits) {
2306 error = -ENOSPC;
2307 goto cleanup;
2308 }
2309 WARN_ON_ONCE(!(current->flags & PF_MEMALLOC_NOFS));
2310 }
2311
2312 error = ext4_reserve_inode_write(handle, inode, &is.iloc);
2313 if (error)
2314 goto cleanup;
2315
2316 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
2317 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
2318 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2319 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
2320 }
2321
2322 error = ext4_xattr_ibody_find(inode, &i, &is);
2323 if (error)
2324 goto cleanup;
2325 if (is.s.not_found)
2326 error = ext4_xattr_block_find(inode, &i, &bs);
2327 if (error)
2328 goto cleanup;
2329 if (is.s.not_found && bs.s.not_found) {
2330 error = -ENODATA;
2331 if (flags & XATTR_REPLACE)
2332 goto cleanup;
2333 error = 0;
2334 if (!value)
2335 goto cleanup;
2336 } else {
2337 error = -EEXIST;
2338 if (flags & XATTR_CREATE)
2339 goto cleanup;
2340 }
2341
2342 if (!value) {
2343 if (!is.s.not_found)
2344 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2345 else if (!bs.s.not_found)
2346 error = ext4_xattr_block_set(handle, inode, &i, &bs);
2347 } else {
2348 error = 0;
2349 /* Xattr value did not change? Save us some work and bail out */
2350 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i))
2351 goto cleanup;
2352 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
2353 goto cleanup;
2354
2355 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2356 (EXT4_XATTR_SIZE(i.value_len) >
2357 EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
2358 i.in_inode = 1;
2359retry_inode:
2360 error = ext4_xattr_ibody_set(handle, inode, &i, &is);
2361 if (!error && !bs.s.not_found) {
2362 i.value = NULL;
2363 error = ext4_xattr_block_set(handle, inode, &i, &bs);
2364 } else if (error == -ENOSPC) {
2365 if (EXT4_I(inode)->i_file_acl && !bs.s.base) {
2366 brelse(bs.bh);
2367 bs.bh = NULL;
2368 error = ext4_xattr_block_find(inode, &i, &bs);
2369 if (error)
2370 goto cleanup;
2371 }
2372 error = ext4_xattr_block_set(handle, inode, &i, &bs);
2373 if (!error && !is.s.not_found) {
2374 i.value = NULL;
2375 error = ext4_xattr_ibody_set(handle, inode, &i,
2376 &is);
2377 } else if (error == -ENOSPC) {
2378 /*
2379 * Xattr does not fit in the block, store at
2380 * external inode if possible.
2381 */
2382 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2383 i.value_len && !i.in_inode) {
2384 i.in_inode = 1;
2385 goto retry_inode;
2386 }
2387 }
2388 }
2389 }
2390 if (!error) {
2391 ext4_xattr_update_super_block(handle, inode->i_sb);
2392 inode->i_ctime = current_time(inode);
2393 if (!value)
2394 no_expand = 0;
2395 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
2396 /*
2397 * The bh is consumed by ext4_mark_iloc_dirty, even with
2398 * error != 0.
2399 */
2400 is.iloc.bh = NULL;
2401 if (IS_SYNC(inode))
2402 ext4_handle_sync(handle);
2403 }
2404 ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
2405
2406cleanup:
2407 brelse(is.iloc.bh);
2408 brelse(bs.bh);
2409 ext4_write_unlock_xattr(inode, &no_expand);
2410 return error;
2411}
2412
2413int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
2414 bool is_create, int *credits)
2415{
2416 struct buffer_head *bh;
2417 int err;
2418
2419 *credits = 0;
2420
2421 if (!EXT4_SB(inode->i_sb)->s_journal)
2422 return 0;
2423
2424 down_read(&EXT4_I(inode)->xattr_sem);
2425
2426 bh = ext4_xattr_get_block(inode);
2427 if (IS_ERR(bh)) {
2428 err = PTR_ERR(bh);
2429 } else {
2430 *credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh,
2431 value_len, is_create);
2432 brelse(bh);
2433 err = 0;
2434 }
2435
2436 up_read(&EXT4_I(inode)->xattr_sem);
2437 return err;
2438}
2439
2440/*
2441 * ext4_xattr_set()
2442 *
2443 * Like ext4_xattr_set_handle, but start from an inode. This extended
2444 * attribute modification is a filesystem transaction by itself.
2445 *
2446 * Returns 0, or a negative error number on failure.
2447 */
2448int
2449ext4_xattr_set(struct inode *inode, int name_index, const char *name,
2450 const void *value, size_t value_len, int flags)
2451{
2452 handle_t *handle;
2453 struct super_block *sb = inode->i_sb;
2454 int error, retries = 0;
2455 int credits;
2456
2457 error = dquot_initialize(inode);
2458 if (error)
2459 return error;
2460
2461retry:
2462 error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE,
2463 &credits);
2464 if (error)
2465 return error;
2466
2467 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
2468 if (IS_ERR(handle)) {
2469 error = PTR_ERR(handle);
2470 } else {
2471 int error2;
2472
2473 error = ext4_xattr_set_handle(handle, inode, name_index, name,
2474 value, value_len, flags);
2475 error2 = ext4_journal_stop(handle);
2476 if (error == -ENOSPC &&
2477 ext4_should_retry_alloc(sb, &retries))
2478 goto retry;
2479 if (error == 0)
2480 error = error2;
2481 }
2482 ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
2483
2484 return error;
2485}
2486
2487/*
2488 * Shift the EA entries in the inode to create space for the increased
2489 * i_extra_isize.
2490 */
2491static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
2492 int value_offs_shift, void *to,
2493 void *from, size_t n)
2494{
2495 struct ext4_xattr_entry *last = entry;
2496 int new_offs;
2497
2498 /* We always shift xattr headers further thus offsets get lower */
2499 BUG_ON(value_offs_shift > 0);
2500
2501 /* Adjust the value offsets of the entries */
2502 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2503 if (!last->e_value_inum && last->e_value_size) {
2504 new_offs = le16_to_cpu(last->e_value_offs) +
2505 value_offs_shift;
2506 last->e_value_offs = cpu_to_le16(new_offs);
2507 }
2508 }
2509 /* Shift the entries by n bytes */
2510 memmove(to, from, n);
2511}
2512
2513/*
2514 * Move xattr pointed to by 'entry' from inode into external xattr block
2515 */
2516static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
2517 struct ext4_inode *raw_inode,
2518 struct ext4_xattr_entry *entry)
2519{
2520 struct ext4_xattr_ibody_find *is = NULL;
2521 struct ext4_xattr_block_find *bs = NULL;
2522 char *buffer = NULL, *b_entry_name = NULL;
2523 size_t value_size = le32_to_cpu(entry->e_value_size);
2524 struct ext4_xattr_info i = {
2525 .value = NULL,
2526 .value_len = 0,
2527 .name_index = entry->e_name_index,
2528 .in_inode = !!entry->e_value_inum,
2529 };
2530 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2531 int error;
2532
2533 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
2534 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
2535 buffer = kmalloc(value_size, GFP_NOFS);
2536 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
2537 if (!is || !bs || !buffer || !b_entry_name) {
2538 error = -ENOMEM;
2539 goto out;
2540 }
2541
2542 is->s.not_found = -ENODATA;
2543 bs->s.not_found = -ENODATA;
2544 is->iloc.bh = NULL;
2545 bs->bh = NULL;
2546
2547 /* Save the entry name and the entry value */
2548 if (entry->e_value_inum) {
2549 error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
2550 if (error)
2551 goto out;
2552 } else {
2553 size_t value_offs = le16_to_cpu(entry->e_value_offs);
2554 memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
2555 }
2556
2557 memcpy(b_entry_name, entry->e_name, entry->e_name_len);
2558 b_entry_name[entry->e_name_len] = '\0';
2559 i.name = b_entry_name;
2560
2561 error = ext4_get_inode_loc(inode, &is->iloc);
2562 if (error)
2563 goto out;
2564
2565 error = ext4_xattr_ibody_find(inode, &i, is);
2566 if (error)
2567 goto out;
2568
2569 /* Remove the chosen entry from the inode */
2570 error = ext4_xattr_ibody_set(handle, inode, &i, is);
2571 if (error)
2572 goto out;
2573
2574 i.value = buffer;
2575 i.value_len = value_size;
2576 error = ext4_xattr_block_find(inode, &i, bs);
2577 if (error)
2578 goto out;
2579
2580 /* Add entry which was removed from the inode into the block */
2581 error = ext4_xattr_block_set(handle, inode, &i, bs);
2582 if (error)
2583 goto out;
2584 error = 0;
2585out:
2586 kfree(b_entry_name);
2587 kfree(buffer);
2588 if (is)
2589 brelse(is->iloc.bh);
2590 if (bs)
2591 brelse(bs->bh);
2592 kfree(is);
2593 kfree(bs);
2594
2595 return error;
2596}
2597
2598static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
2599 struct ext4_inode *raw_inode,
2600 int isize_diff, size_t ifree,
2601 size_t bfree, int *total_ino)
2602{
2603 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
2604 struct ext4_xattr_entry *small_entry;
2605 struct ext4_xattr_entry *entry;
2606 struct ext4_xattr_entry *last;
2607 unsigned int entry_size; /* EA entry size */
2608 unsigned int total_size; /* EA entry size + value size */
2609 unsigned int min_total_size;
2610 int error;
2611
2612 while (isize_diff > ifree) {
2613 entry = NULL;
2614 small_entry = NULL;
2615 min_total_size = ~0U;
2616 last = IFIRST(header);
2617 /* Find the entry best suited to be pushed into EA block */
2618 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
2619 /* never move system.data out of the inode */
2620 if ((last->e_name_len == 4) &&
2621 (last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) &&
2622 !memcmp(last->e_name, "data", 4))
2623 continue;
2624 total_size = EXT4_XATTR_LEN(last->e_name_len);
2625 if (!last->e_value_inum)
2626 total_size += EXT4_XATTR_SIZE(
2627 le32_to_cpu(last->e_value_size));
2628 if (total_size <= bfree &&
2629 total_size < min_total_size) {
2630 if (total_size + ifree < isize_diff) {
2631 small_entry = last;
2632 } else {
2633 entry = last;
2634 min_total_size = total_size;
2635 }
2636 }
2637 }
2638
2639 if (entry == NULL) {
2640 if (small_entry == NULL)
2641 return -ENOSPC;
2642 entry = small_entry;
2643 }
2644
2645 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
2646 total_size = entry_size;
2647 if (!entry->e_value_inum)
2648 total_size += EXT4_XATTR_SIZE(
2649 le32_to_cpu(entry->e_value_size));
2650 error = ext4_xattr_move_to_block(handle, inode, raw_inode,
2651 entry);
2652 if (error)
2653 return error;
2654
2655 *total_ino -= entry_size;
2656 ifree += total_size;
2657 bfree -= total_size;
2658 }
2659
2660 return 0;
2661}
2662
2663/*
2664 * Expand an inode by new_extra_isize bytes when EAs are present.
2665 * Returns 0 on success or negative error number on failure.
2666 */
2667int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
2668 struct ext4_inode *raw_inode, handle_t *handle)
2669{
2670 struct ext4_xattr_ibody_header *header;
2671 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2672 static unsigned int mnt_count;
2673 size_t min_offs;
2674 size_t ifree, bfree;
2675 int total_ino;
2676 void *base, *end;
2677 int error = 0, tried_min_extra_isize = 0;
2678 int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize);
2679 int isize_diff; /* How much do we need to grow i_extra_isize */
2680
2681retry:
2682 isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
2683 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
2684 return 0;
2685
2686 header = IHDR(inode, raw_inode);
2687
2688 /*
2689 * Check if enough free space is available in the inode to shift the
2690 * entries ahead by new_extra_isize.
2691 */
2692
2693 base = IFIRST(header);
2694 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
2695 min_offs = end - base;
2696 total_ino = sizeof(struct ext4_xattr_ibody_header) + sizeof(u32);
2697
2698 error = xattr_check_inode(inode, header, end);
2699 if (error)
2700 goto cleanup;
2701
2702 ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino);
2703 if (ifree >= isize_diff)
2704 goto shift;
2705
2706 /*
2707 * Enough free space isn't available in the inode, check if
2708 * EA block can hold new_extra_isize bytes.
2709 */
2710 if (EXT4_I(inode)->i_file_acl) {
2711 struct buffer_head *bh;
2712
2713 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2714 if (IS_ERR(bh)) {
2715 error = PTR_ERR(bh);
2716 goto cleanup;
2717 }
2718 error = ext4_xattr_check_block(inode, bh);
2719 if (error) {
2720 brelse(bh);
2721 goto cleanup;
2722 }
2723 base = BHDR(bh);
2724 end = bh->b_data + bh->b_size;
2725 min_offs = end - base;
2726 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base,
2727 NULL);
2728 brelse(bh);
2729 if (bfree + ifree < isize_diff) {
2730 if (!tried_min_extra_isize && s_min_extra_isize) {
2731 tried_min_extra_isize++;
2732 new_extra_isize = s_min_extra_isize;
2733 goto retry;
2734 }
2735 error = -ENOSPC;
2736 goto cleanup;
2737 }
2738 } else {
2739 bfree = inode->i_sb->s_blocksize;
2740 }
2741
2742 error = ext4_xattr_make_inode_space(handle, inode, raw_inode,
2743 isize_diff, ifree, bfree,
2744 &total_ino);
2745 if (error) {
2746 if (error == -ENOSPC && !tried_min_extra_isize &&
2747 s_min_extra_isize) {
2748 tried_min_extra_isize++;
2749 new_extra_isize = s_min_extra_isize;
2750 goto retry;
2751 }
2752 goto cleanup;
2753 }
2754shift:
2755 /* Adjust the offsets and shift the remaining entries ahead */
2756 ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize
2757 - new_extra_isize, (void *)raw_inode +
2758 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
2759 (void *)header, total_ino);
2760 EXT4_I(inode)->i_extra_isize = new_extra_isize;
2761
2762cleanup:
2763 if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) {
2764 ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.",
2765 inode->i_ino);
2766 mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count);
2767 }
2768 return error;
2769}
2770
2771#define EIA_INCR 16 /* must be 2^n */
2772#define EIA_MASK (EIA_INCR - 1)
2773
2774/* Add the large xattr @inode into @ea_inode_array for deferred iput().
2775 * If @ea_inode_array is new or full it will be grown and the old
2776 * contents copied over.
2777 */
2778static int
2779ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
2780 struct inode *inode)
2781{
2782 if (*ea_inode_array == NULL) {
2783 /*
2784 * Start with 15 inodes, so it fits into a power-of-two size.
2785 * If *ea_inode_array is NULL, this is essentially offsetof()
2786 */
2787 (*ea_inode_array) =
2788 kmalloc(offsetof(struct ext4_xattr_inode_array,
2789 inodes[EIA_MASK]),
2790 GFP_NOFS);
2791 if (*ea_inode_array == NULL)
2792 return -ENOMEM;
2793 (*ea_inode_array)->count = 0;
2794 } else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
2795 /* expand the array once all 15 + n * 16 slots are full */
2796 struct ext4_xattr_inode_array *new_array = NULL;
2797 int count = (*ea_inode_array)->count;
2798
2799 /* if new_array is NULL, this is essentially offsetof() */
2800 new_array = kmalloc(
2801 offsetof(struct ext4_xattr_inode_array,
2802 inodes[count + EIA_INCR]),
2803 GFP_NOFS);
2804 if (new_array == NULL)
2805 return -ENOMEM;
2806 memcpy(new_array, *ea_inode_array,
2807 offsetof(struct ext4_xattr_inode_array, inodes[count]));
2808 kfree(*ea_inode_array);
2809 *ea_inode_array = new_array;
2810 }
2811 (*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
2812 return 0;
2813}
2814
2815/*
2816 * ext4_xattr_delete_inode()
2817 *
2818 * Free extended attribute resources associated with this inode. Traverse
2819 * all entries and decrement reference on any xattr inodes associated with this
2820 * inode. This is called immediately before an inode is freed. We have exclusive
2821 * access to the inode. If an orphan inode is deleted it will also release its
2822 * references on xattr block and xattr inodes.
2823 */
2824int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
2825 struct ext4_xattr_inode_array **ea_inode_array,
2826 int extra_credits)
2827{
2828 struct buffer_head *bh = NULL;
2829 struct ext4_xattr_ibody_header *header;
2830 struct ext4_iloc iloc = { .bh = NULL };
2831 struct ext4_xattr_entry *entry;
2832 struct inode *ea_inode;
2833 int error;
2834
2835 error = ext4_journal_ensure_credits(handle, extra_credits,
2836 ext4_free_metadata_revoke_credits(inode->i_sb, 1));
2837 if (error < 0) {
2838 EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
2839 goto cleanup;
2840 }
2841
2842 if (ext4_has_feature_ea_inode(inode->i_sb) &&
2843 ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
2844
2845 error = ext4_get_inode_loc(inode, &iloc);
2846 if (error) {
2847 EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
2848 goto cleanup;
2849 }
2850
2851 error = ext4_journal_get_write_access(handle, iloc.bh);
2852 if (error) {
2853 EXT4_ERROR_INODE(inode, "write access (error %d)",
2854 error);
2855 goto cleanup;
2856 }
2857
2858 header = IHDR(inode, ext4_raw_inode(&iloc));
2859 if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
2860 ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
2861 IFIRST(header),
2862 false /* block_csum */,
2863 ea_inode_array,
2864 extra_credits,
2865 false /* skip_quota */);
2866 }
2867
2868 if (EXT4_I(inode)->i_file_acl) {
2869 bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
2870 if (IS_ERR(bh)) {
2871 error = PTR_ERR(bh);
2872 if (error == -EIO) {
2873 EXT4_ERROR_INODE_ERR(inode, EIO,
2874 "block %llu read error",
2875 EXT4_I(inode)->i_file_acl);
2876 }
2877 bh = NULL;
2878 goto cleanup;
2879 }
2880 error = ext4_xattr_check_block(inode, bh);
2881 if (error)
2882 goto cleanup;
2883
2884 if (ext4_has_feature_ea_inode(inode->i_sb)) {
2885 for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
2886 entry = EXT4_XATTR_NEXT(entry)) {
2887 if (!entry->e_value_inum)
2888 continue;
2889 error = ext4_xattr_inode_iget(inode,
2890 le32_to_cpu(entry->e_value_inum),
2891 le32_to_cpu(entry->e_hash),
2892 &ea_inode);
2893 if (error)
2894 continue;
2895 ext4_xattr_inode_free_quota(inode, ea_inode,
2896 le32_to_cpu(entry->e_value_size));
2897 iput(ea_inode);
2898 }
2899
2900 }
2901
2902 ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
2903 extra_credits);
2904 /*
2905 * Update i_file_acl value in the same transaction that releases
2906 * block.
2907 */
2908 EXT4_I(inode)->i_file_acl = 0;
2909 error = ext4_mark_inode_dirty(handle, inode);
2910 if (error) {
2911 EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
2912 error);
2913 goto cleanup;
2914 }
2915 ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR);
2916 }
2917 error = 0;
2918cleanup:
2919 brelse(iloc.bh);
2920 brelse(bh);
2921 return error;
2922}
2923
2924void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
2925{
2926 int idx;
2927
2928 if (ea_inode_array == NULL)
2929 return;
2930
2931 for (idx = 0; idx < ea_inode_array->count; ++idx)
2932 iput(ea_inode_array->inodes[idx]);
2933 kfree(ea_inode_array);
2934}
2935
2936/*
2937 * ext4_xattr_block_cache_insert()
2938 *
2939 * Create a new entry in the extended attribute block cache, and insert
2940 * it unless such an entry is already in the cache.
2941 *
2942 * Returns 0, or a negative error number on failure.
2943 */
2944static void
2945ext4_xattr_block_cache_insert(struct mb_cache *ea_block_cache,
2946 struct buffer_head *bh)
2947{
2948 struct ext4_xattr_header *header = BHDR(bh);
2949 __u32 hash = le32_to_cpu(header->h_hash);
2950 int reusable = le32_to_cpu(header->h_refcount) <
2951 EXT4_XATTR_REFCOUNT_MAX;
2952 int error;
2953
2954 if (!ea_block_cache)
2955 return;
2956 error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash,
2957 bh->b_blocknr, reusable);
2958 if (error) {
2959 if (error == -EBUSY)
2960 ea_bdebug(bh, "already in cache");
2961 } else
2962 ea_bdebug(bh, "inserting [%x]", (int)hash);
2963}
2964
2965/*
2966 * ext4_xattr_cmp()
2967 *
2968 * Compare two extended attribute blocks for equality.
2969 *
2970 * Returns 0 if the blocks are equal, 1 if they differ, and
2971 * a negative error number on errors.
2972 */
2973static int
2974ext4_xattr_cmp(struct ext4_xattr_header *header1,
2975 struct ext4_xattr_header *header2)
2976{
2977 struct ext4_xattr_entry *entry1, *entry2;
2978
2979 entry1 = ENTRY(header1+1);
2980 entry2 = ENTRY(header2+1);
2981 while (!IS_LAST_ENTRY(entry1)) {
2982 if (IS_LAST_ENTRY(entry2))
2983 return 1;
2984 if (entry1->e_hash != entry2->e_hash ||
2985 entry1->e_name_index != entry2->e_name_index ||
2986 entry1->e_name_len != entry2->e_name_len ||
2987 entry1->e_value_size != entry2->e_value_size ||
2988 entry1->e_value_inum != entry2->e_value_inum ||
2989 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
2990 return 1;
2991 if (!entry1->e_value_inum &&
2992 memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
2993 (char *)header2 + le16_to_cpu(entry2->e_value_offs),
2994 le32_to_cpu(entry1->e_value_size)))
2995 return 1;
2996
2997 entry1 = EXT4_XATTR_NEXT(entry1);
2998 entry2 = EXT4_XATTR_NEXT(entry2);
2999 }
3000 if (!IS_LAST_ENTRY(entry2))
3001 return 1;
3002 return 0;
3003}
3004
3005/*
3006 * ext4_xattr_block_cache_find()
3007 *
3008 * Find an identical extended attribute block.
3009 *
3010 * Returns a pointer to the block found, or NULL if such a block was
3011 * not found or an error occurred.
3012 */
3013static struct buffer_head *
3014ext4_xattr_block_cache_find(struct inode *inode,
3015 struct ext4_xattr_header *header,
3016 struct mb_cache_entry **pce)
3017{
3018 __u32 hash = le32_to_cpu(header->h_hash);
3019 struct mb_cache_entry *ce;
3020 struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode);
3021
3022 if (!ea_block_cache)
3023 return NULL;
3024 if (!header->h_hash)
3025 return NULL; /* never share */
3026 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
3027 ce = mb_cache_entry_find_first(ea_block_cache, hash);
3028 while (ce) {
3029 struct buffer_head *bh;
3030
3031 bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
3032 if (IS_ERR(bh)) {
3033 if (PTR_ERR(bh) == -ENOMEM)
3034 return NULL;
3035 bh = NULL;
3036 EXT4_ERROR_INODE(inode, "block %lu read error",
3037 (unsigned long)ce->e_value);
3038 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
3039 *pce = ce;
3040 return bh;
3041 }
3042 brelse(bh);
3043 ce = mb_cache_entry_find_next(ea_block_cache, ce);
3044 }
3045 return NULL;
3046}
3047
3048#define NAME_HASH_SHIFT 5
3049#define VALUE_HASH_SHIFT 16
3050
3051/*
3052 * ext4_xattr_hash_entry()
3053 *
3054 * Compute the hash of an extended attribute.
3055 */
3056static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value,
3057 size_t value_count)
3058{
3059 __u32 hash = 0;
3060
3061 while (name_len--) {
3062 hash = (hash << NAME_HASH_SHIFT) ^
3063 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
3064 *name++;
3065 }
3066 while (value_count--) {
3067 hash = (hash << VALUE_HASH_SHIFT) ^
3068 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
3069 le32_to_cpu(*value++);
3070 }
3071 return cpu_to_le32(hash);
3072}
3073
3074#undef NAME_HASH_SHIFT
3075#undef VALUE_HASH_SHIFT
3076
3077#define BLOCK_HASH_SHIFT 16
3078
3079/*
3080 * ext4_xattr_rehash()
3081 *
3082 * Re-compute the extended attribute hash value after an entry has changed.
3083 */
3084static void ext4_xattr_rehash(struct ext4_xattr_header *header)
3085{
3086 struct ext4_xattr_entry *here;
3087 __u32 hash = 0;
3088
3089 here = ENTRY(header+1);
3090 while (!IS_LAST_ENTRY(here)) {
3091 if (!here->e_hash) {
3092 /* Block is not shared if an entry's hash value == 0 */
3093 hash = 0;
3094 break;
3095 }
3096 hash = (hash << BLOCK_HASH_SHIFT) ^
3097 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
3098 le32_to_cpu(here->e_hash);
3099 here = EXT4_XATTR_NEXT(here);
3100 }
3101 header->h_hash = cpu_to_le32(hash);
3102}
3103
3104#undef BLOCK_HASH_SHIFT
3105
3106#define HASH_BUCKET_BITS 10
3107
3108struct mb_cache *
3109ext4_xattr_create_cache(void)
3110{
3111 return mb_cache_create(HASH_BUCKET_BITS);
3112}
3113
3114void ext4_xattr_destroy_cache(struct mb_cache *cache)
3115{
3116 if (cache)
3117 mb_cache_destroy(cache);
3118}
3119